High temperature superconducting films and methods for modifying and creating same

ABSTRACT

Operational characteristics of an high temperature superconducting (“HTS”) film comprised of an HTS material may be improved by depositing a modifying material onto appropriate surfaces of the HTS film to create a modified HTS film. In some implementations of the invention, the HTS film may be in the form of a “c-film.” In some implementations of the invention, the HTS film may be in the form of an “a-b film,” an “a-film” or a “b-film.” The modified HTS film has improved operational characteristics over the HTS film alone or without the modifying material. Such operational characteristics may include operating in a superconducting state at increased temperatures, carrying additional electrical charge, operating with improved magnetic properties, operating with improved mechanic properties or other improved operational characteristics. In some implementations of the invention, the HTS material is a mixed-valence copper-oxide perovskite, such as, but not limited to YBCO. In some implementations of the invention, the modifying material is a conductive material that bonds easily to oxygen, such as, but not limited to, chromium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/896,876, filed on Oct. 2, 2010, and entitled “High TemperatureSuperconducting Films and Methods for Modifying and Creating Same,”which claims priority to U.S. Provisional Application No. 61/248,134,filed on Oct. 2, 2009, and entitled “High Temperature SuperconductingMaterials and Methods for Modifying or Creating Same,” both of which areincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The invention is generally related to superconducing films or tapes,including high temperature superconducting films or tapes (“HTS films”or “HTS tapes”), and more particularly to modifying existing HTS filmsand/or creating new HTS films that operate with improved operatingcharacteristics.

BACKGROUND OF THE INVENTION

Ongoing research attempts to achieve new materials with improvedoperational characteristics, for example, reduced electrical resistanceat higher temperatures over existing materials, includingsuperconducting materials. Scientists have theorized a possibleexistence of a “perfect conductor,” or a material that exhibitsresistance similar to that of superconducting materials in theirsuperconducting state, but that may not necessarily demonstrate all theconventionally accepted characteristics of a superconducting material.

Nothwithstanding their name, conventional high temperaturesuperconducting (“HTS”) materials still operate at very lowtemperatures. In fact, most commonly used HTS materials still requireuse of a cooling system that uses liquids with very low boiling points(e.g., liquid nitrogen). Such cooling systems increase implementationcosts and discourage widespread commercial and consumer use and/orapplication of such materials.

What is needed are HTS films with improved operating characteristics;

mechanisms for modifying known HTS films so that the modified HTS filmsoperate with improved operating characteristics; and/or techniques fordesigning and fabricating new HTS films.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate various exemplary implementationsof the invention and together with the detailed description serve toexplain various principles and/or aspects of the invention.

FIG. 1 illustrates a crystalline structure of an exemplary HTS materialas viewed from a first perspective.

FIG. 2 illustrates a crystalline structure of an exemplary HTS materialas viewed from a second perspective.

FIG. 3 illustrates a crystalline structure of an exemplary HTS materialas viewed from a second perspective.

FIG. 4 illustrates a conceptual mechanical model of a crystallinestructure of an HTS material.

FIG. 5 illustrates a conceptual mechanical model of an improvedcrystalline structure, according to various implementations of theinvention, of an HTS material.

FIG. 6 illustrates a conceptual mechanical model of an improvedcrystalline structure, according to various implementations of theinvention, of an HTS material.

FIG. 7 illustrates a conceptual mechanical model of an improvedcrystalline structure, according to various implementations of theinvention, of an exemplary HTS material.

FIG. 8 illustrates a conceptual mechanical model of an improvedcrystalline structure, according to various implementations of theinvention, of an HTS material.

FIG. 9 illustrates a conceptual mechanical model of an improvedcrystalline structure, according to various implementations of theinvention, of an HTS material.

FIG. 10 illustrates a modified crystalline structure, according tovarious implementations of the invention, of an HTS material as viewedfrom a second perspective.

FIG. 11 illustrates a modified crystalline structure, according tovarious implementations of the invention, of an HTS material as viewedfrom a first perspective.

FIG. 12 is a flowchart for producing a modified material from an HTSmaterial according to various implementations of the invention.

FIGS. 13A-13J illustrate preparing a modified HTS material according tovarious implementations of the invention.

FIG. 14 is a flowchart for depositing a modifying material onto an HTSmaterial according to various implementations of the invention.

FIG. 15 illustrates a test bed useful for determining variousoperational characteristics of a modified HTS material according tovarious implementations of the invention.

FIGS. 16A-16G illustrate test results demonstrating various operationalcharacteristics of a modified HTS material.

FIG. 17 illustrates a crystalline structure of an exemplary HTS materialas viewed from a second perspective.

FIG. 18 illustrates a crystalline structure of an exemplary HTS materialas viewed from a second perspective.

FIG. 19 illustrates a crystalline structure of an exemplary HTS materialas viewed from a second perspective.

FIG. 20 illustrates an arrangement of an HTS material and a modifyingmaterial useful for propagating electrical charge according to variousimplementations of the invention.

FIG. 21 illustrates a single unit cell of an exemplary HTS material.

FIG. 22 illustrates a crystalline structure of an exemplary HTS materialas viewed from a second perspective.

FIG. 23 illustrates multiple layers of crystalline structures of anexemplary surface-modified HTS material according to variousimplementations of the invention.

FIG. 24 illustrates test results demonstrating various operationalcharacteristics of a modified HTS material, namely with chromium as amodifying material and YBCO as an HTS material, in accordance withvarious implementations of the invention.

FIG. 25 illustrates test results demonstrating various operationalcharacteristics of a modified HTS material, namely with vanadium as amodifying material and YBCO as an HTS material, in accordance withvarious implementations of the invention.

FIG. 26 illustrates test results demonstrating various operationalcharacteristics of a modified HTS material, namely with bismuth as amodifying material and YBCO as an HTS material, in accordance withvarious implementations of the invention.

FIG. 27 illustrates test results demonstrating various operationalcharacteristics of a modified HTS material, namely with copper as amodifying material and YBCO as an HTS material, in accordance withvarious implementations of the invention.

FIG. 28 illustrates test results demonstrating various operationalcharacteristics of a modified HTS material, namely with cobalt as amodifying material and YBCO as an HTS material, in accordance withvarious implementations of the invention.

FIG. 29 illustrates test results demonstrating various operationalcharacteristics of a modified HTS material, namely with titanium as amodifying material and YBCO as an HTS material, in accordance withvarious implementations of the invention.

FIG. 30 illustrates a crystalline structure of an exemplary HTS materialas viewed from a third perspective.

FIG. 31 illustrates a reference frame useful for describing variousimplementations of the invention.

FIG. 32 illustrates a c-film of HTS material according to variousimplementations of the invention.

FIG. 33 illustrates a c-film with appropriate surfaces of HTS materialaccording to various implementations of the invention.

FIG. 34 illustrates a c-film with appropriate surfaces of HTS materialaccording to various implementations of the invention.

FIG. 35 illustrates a modifying material layered onto appropriatesurfaces of HTS material according to various implementations of theinvention.

FIG. 36 illustrates a modifying material layered onto appropriatesurfaces of HTS material according to various implementations of theinvention.

FIG. 37 illustrates a c-film with an etched surface includingappropriate surfaces of HTS material according to variousimplementations of the invention.

FIG. 38 illustrates a modifying material layered onto an etched surfaceof a c-film with appropriate surfaces of HTS material according tovarious implementations of the invention.

FIG. 39 illustrates an a-b film, including an optional substrate, withappropriate surfaces of HTS material according to variousimplementations of the invention.

FIG. 40 illustrates a modifying material layered onto appropriatesurfaces of HTS material of an a-b film according to variousimplementations of the invention.

FIG. 41 illustrates various exemplary arrangements of layers of HTSmaterial, modifying material, buffer or insulating layers, and/orsubstrates in accordance with various implementations of the invention.

FIG. 42 illustrates a process for forming a modified HTS materialaccording to various implementations of the invention.

FIG. 43 illustrates an example of additional processing that may beperformed according to various implementations of the invention.

FIG. 44 illustrates a process for forming a modified HTS materialaccording to various implementations of the invention.

FIG. 45 illustrates a crystalline structure of an exemplarysuperconducting material as viewed from a second perspective.

FIG. 46 illustrates a crystalline structure of an exemplarysuperconducting material as viewed from a second perspective.

SUMMARY OF THE INVENTION

Generally speaking, various implementations of the invention relate tomodifying existing HTS materials and/or processes for creating new HTSmaterials. In some implementations of the invention, existing HTSmaterials are modified to create modified HTS materials with improvedoperating characteristics. These operating characteristics may include,but are not limited to, operating with reduced resistance at highertemperatures, operating in a superconducting state at highertemperatures, operating with increased charge carrying capacity at thesame (or higher) temperatures, operating with improved magneticproperties, operating with improved mechanical properties, and/or otherimproved operating characteristics.

While the aspects and implementations of the invention are described inreference to, for example, HTS materials and HTS films, such aspects andimplementations apply to superconducting materials and superconductingfilms as would be appreciated. By way of example, variousimplementations of the invention may utilize a material selected from abroader class of superconducting materials of which HTS materials are asubset. For example, various implementations of the invention mayutilize various superconducting materials such as, but not limited to,iron pnictide materials, magnesium diboride, and other superconductingmaterials.

In some implementations of the invention, a method comprises layering amodifying material onto an appropriate surface of an HTS film to createa modified HTS film, where the modified HTS film has improvedoperational characteristics over those of the HTS film without themodifying material.

In some implementations of the invention, a method comprises forming anappropriate surface on or within an HTS film and layering a modifyingmaterial onto the appropriate surface of the HTS film to create amodified HTS film, where the modified HTS film has improved operationalcharacteristics over those of the HTS film alone or without themodifying material. In further implementations of in the invention, theappropriate surface is not substantially parallel to a c-plane of theHTS film.

In various implementations of the invention, the improved operationalcharacteristics include operating in a superconducting state at highertemperatures, operating with increased charge carrying capacity at thesame or higher temperatures, operating with improved magneticproperties, or operating with improved mechanical properties.

In some implementations of the invention, layering a modifying materialonto an appropriate surface of the HTS film comprises depositing themodifying material onto the appropriate surface of the HTS film. Infurther implementations of the invention, depositing the modifyingmaterial onto the appropriate surface of the HTS film comprises usingMBE, PLD, or CVD.

In some implementations of the invention, layering a modifying materialonto an appropriate surface of the HTS film comprises layering themodifying material onto a face of the HTS film that is not substantiallyparallel to a c-plane of a crystalline structure of an HTS material inthe HTS film. In some implementations of the invention, layering amodifying material onto an appropriate surface of the HTS film compriseslayering the modifying material onto a face of the HTS material that isparallel to an ab-plane of a crystalline structure of the HTS material.In some implementations of the invention, layering a modifying materialonto appropriate surface of the HTS film comprises layering themodifying material onto a face of the HTS material that is parallel toan a-plane or a b-plane of a crystalline structure of the HTS material.

In some implementations of the invention, layering a modifying materialonto an appropriate surface of the HTS film comprises layering chromium,copper, bismuth, cobalt, vanadium, titanium, rhodium, beryllium,gallium, or selenium onto the appropriate surface of the HTS film.

In some implementations of the invention, forming the appropriatesurface on or within the HTS film comprises exposing the appropriatesurface on or within the HTS film.

In some implementations of the invention, forming the appropriatesurface on or within the HTS film comprises layering the HTS materialonto a substrate in a manner that orients a particular axis of thecrystalline structure of the HTS material along a principal axis of thesubstrate, wherein the particular axis is a line within the c-plane ofthe crystalline structure of the HTS material. In furtherimplementations of the invention, the particular axis is the a-axis orthe b-axis.

In some implementations of the invention, exposing the appropriatesurface of the HTS film comprises etching a primary surface of the HTSfilm to increase a surface area of the primary surface.

In some implementations of the invention, exposing the appropriatesurface of the HTS film comprises creating a pattern in a primarysurface of the HTS film thereby exposing one or more appropriatesurfaces of the HTS film.

In some implementations of the invention, creating a pattern in aprimary surface of the HTS film comprises inscribing a groove in the HTSmaterial of the HTS film. In some implementations of the invention, thegroove is substantially in the direction of the principal axis of theHTS film. In some implementations of the invention, the groove has adepth substantially equal to a thickness of the HTS material. In someimplementations of the invention, the groove has a depth less than athickness of the HTS material. In some implementations of the invention,the width of the at least one groove is greater than 10 nm. In someimplementations of the invention, a modifying material is deposited intothe groove.

In some implementations of the invention, a method comprises creating atleast one groove in the primary surface of an HTS film, thereby exposinga face of the HTS film, the exposed face being a face parallel to anab-plane of the crystalline structure of an HTS material in the HTS filmand depositing a modifying material onto the exposed face.

In some implementations of the invention, depositing a modifyingmaterial onto the exposed face comprises depositing a single unit layerof the modifying material onto the exposed face. In some implementationsof the invention, depositing a modifying material onto the exposed facecomprises depositing two or more unit layers of the modifying materialonto the exposed face.

In some implementations of the invention, layering a modifying materialonto an appropriate surface of the HTS film comprises layering themodifying material onto a face of the HTS film that is not substantiallyparallel to a c-plane of the HTS film.

In some implementations of the invention, a method comprises bonding amodifying material to an HTS material to form a modified HTS material,where the modified HTS material operates at a temperature greater thanthat of the HTS material alone or without the modifying material.

In some implementations, a modifying material is layered onto an HTSmaterial to form a modified HTS material that operates with an improvedoperating characteristic over that of the HTS material alone or withouta modifying material. HTS materials may be selected from a family of HTSmaterials referred to as mixed-valence copper-oxide perovskites. In someimplementations, modifying materials may be selected from any one orcombination of the following: chromium (Cr), copper (Cu), bismuth (Bi),cobalt (Co), vanadium (V), titanium (Ti), rhodium (Rh), beryllium (Be),gallium (Ga), and/or selenium (Se).

In some implementations of the invention, a composite comprises an HTSmaterial, and a modifying material bonded to the HTS material such thatthe composite operates in a superconducting state at a temperaturegreater than that of the HTS material alone or without the modifyingmaterial.

In some implementations of the invention, a composite comprises a firstlayer comprising an HTS material, and a second layer comprising amodifying material, where the second layer is bonded to the first layer.In some implementations of the invention, a composite comprises a firstlayer comprising an HTS material, a second layer comprising a modifyingmaterial, where the second layer is bonded to the first layer, a thirdlayer comprising the HTS material, and a fourth layer of the modifyingmaterial, where the third layer is bonded to the fourth layer. In someimplementations of the invention, the second layer is deposited onto thefirst layer. In some implementations of the invention, the first layeris deposited onto the second layer. In some implementations of theinvention, the HTS material of the first layer is formed on the secondlayer. In some implementations of the invention, the first layer has athickness of at least a single crystalline unit cell of the HTSmaterial. In some implementations of the invention, the first layer hasa thickness of several crystalline unit cells of the HTS material. Insome implementations of the invention, the second layer has a thicknessof at least a single unit (e.g., atom, molecule, crystal, unit cell, orother unit) of the modifying material. In some implementations of theinvention, the second layer has a thickness of several units of themodifying material.

In some implementations of the invention, a composite comprises a firstlayer comprising YBCO, and a second layer comprising a modifyingmaterial, wherein the modifying material of the second layer is bondedto the YBCO of the first layer, wherein the modifying material is anelement selected as any one or more of the group including: chromium,copper, bismuth, cobalt, vanadium, titanium, rhodium, beryllium,gallium, or selenium. In some implementations of the invention, themodifying material of the second layer is bonded to a face of the YBCOof the first layer, where the face is substantially parallel to a c-axisof the YBCO. In some implementations of the invention, the modifyingmaterial of the second layer is bonded to a face of the YBCO of thefirst layer, where the face is substantially parallel to an ab-plane ofthe YBCO. In some implementations of the invention, the modifyingmaterial of the second layer is bonded to a face of the YBCO of thefirst layer, where the face is substantially perpendicular to a b-axisof the YBCO. In some implementations of the invention, the modifyingmaterial of the second layer is bonded to a face of the YBCO of thefirst layer, where the face is substantially perpendicular to an a-axisof the YBCO.

In some implementations of the invention, the HTS material comprises amixed-valence copper-oxide perovskite material. In some implementationsof the invention, the mixed-valence copper-oxide perovskite material maybe selected from the groups generically referred to as LaBaCuO, LSCO,YBCO, BSCCO, TBCCO, HgBa₂Ca₂Cu₃O_(x), or other mixed-valencecopper-oxide perovskite materials. In some implementations of theinvention, the modifying material may be a conductive material. In someimplementations of the invention, the modifying material may be amaterial that bonds easily with oxygen. In some implementations of theinvention, the modifying material may be a conductive material thatbonds easily with oxygen (“oxygen bonding bonding conductive material”).In some implementations of the invention, the modifying material may beany one or combination of chromium, copper, bismuth, cobalt, vanadium,titanium, rhodium, beryllium, gallium, and/or selenium. In someimplementations of the invention, various combinations of the HTSmaterials and the modifying materials may be used. In someimplementations of the invention, the HTS material is YBCO and themodifying material is chromium.

In some implementations of the invention, the composite of the HTSmaterial with the modifying material operates at a higher temperaturethan the HTS material alone or without the modifying material. In someimplementations of the invention, the composite demonstrates HTS at ahigher temperature than that of the HTS material alone or without themodifying material. In some implementations of the invention, thecomposite transitions from a non-superconducting state to asuperconducting state at a temperature higher than that of the HTSmaterial alone or without the modifying material. In someimplementations of the invention, the composite has a transitiontemperature greater than that of the HTS material alone or without themodifying material. In some implementations of the invention, thecomposite carries a greater amount of current in a superconducting statethan that carried by the HTS material alone or without the modifyingmaterial.

In some implementations of the invention, the composite operates in asuperconducting state at a higher temperature than the HTS materialalone or without the modifying material. In some implementations of theinvention, the composite operates in a superconducting state attemperatures greater than any one of the following temperatures: 200K,210K, 220K, 230K, 240K, 250K, 260K, 270K, 280K, 290K, 300K, or 310K.

In some implementations of the invention where the HTS material is YBCO,the composite has improved operating characteristics over those of YBCOalone or without the modifying material. In some implementations of theinvention where the HTS material is YBCO, the composite operates at ahigher temperature than that of YBCO alone or without the modifyingmaterial. In some implementations of the invention where the HTSmaterial is YBCO, the composite exhibits the resistance phenomenon at ahigher temperature than that of YBCO alone or without the modifyingmaterial. In some implementations of the invention where the HTSmaterial is YBCO, the composite transitions from a non-superconductingstate to a superconducting state at a temperature higher than that ofYBCO alone or without the modifying material. In some implementations ofthe invention where the HTS material is YBCO, the composite has atransition temperature greater than that of YBCO alone or without themodifying material. In some implementations of the invention where theHTS material is YBCO, the composite carries a greater amount of currentin a superconducting state than that carried by YBCO in itssuperconducting state alone or without the modifying material.

In some implementations of the invention, an HTS film comprises a firstlayer comprised of an HTS material, and a second layer comprised of amodifying material bonded to the HTS material of the first layer, wherethe HTS film has an improved operational characteristic over theoperational characteristics of the HTS material without the modifyingmaterial.

DETAILED DESCRIPTION

Various features, advantages, and implementations of the invention maybe set forth or be apparent from consideration of the following detaileddescription, the drawings, and the claims. It is to be understood thatthe detailed description and the drawings are exemplary and intended toprovide further explanation without limiting the scope of the inventionexcept as set forth in the claims.

Various implementations of the invention are related to HTS films (whichinclude HTS materials), and more particularly to modifying existing HTSfilms and/or creating new HTS films that operate with improved operatingcharacteristics. The novel HTS films can encompass, for example,composites, products, processes of manufacture, product-by-process,methods of making novel HTS films, for example, to obtain a newtechnical effect.

For purposes of this description, operating characteristics with regardto HTS materials and/or various implementations of the invention mayinclude, but are not limited to, a resistance of the HTS material in itssuperconducting state, a transition temperature of the HTS material toits superconducting state, a charge propagating capacity of the HTSmaterial in its superconducting state, one or more magnetic propertiesof the HTS material, one or more mechanical properties of the HTSmaterial, and/or other operating characteristics of the HTS material.

Incremental improvements in a transition temperature (sometimes alsoreferred to as a critical temperature) of HTS materials, appear to bebased on trial and error rather than an understanding of the mechanismsby which HTS materials operate. Without such an understanding, furtherimprovements to a transition temperature (or other operatingcharacteristic) of the known HTS materials (or classes thereof) as wellas design of new HTS materials are limited. As generally understood, thetransition temperature is a temperature below which the HTS material“operates” in its superconducting state. At temperatures above thetransition temperature, the HTS material ceases to operate in itssuperconducting state and is referred to as being in its “normal” ornon-superconducting state. In other words, the transition temperaturecorresponds to a temperature at which the HTS material changes betweenits non-superconducting state and its superconducting state. As would beappreciated, for some HTS materials, the transition temperature may be arange of temperatures over which the HTS material changes between itsnon-superconducting state and its superconducting state. As would alsobe appreciated, the HTS material may have hysteresis in its transitiontemperature with one transition temperature as the HTS material warmsand another transition temperature as the HTS material cools.

FIG. 31 illustrates a reference frame 3100 which may be used to describevarious implementations of the invention. Reference frame 3100 includesa set of axes referred to as an a-axis, a b-axis, and a c-axis. Forpurposes of this description: reference to the a-axis includes thea-axis and any other axis parallel thereto; reference to the b-axisincludes the b-axis and any other axis parallel thereto; and referenceto the c-axis includes the c-axis and any other axis parallel thereto.Various pairs of the axes form a set of planes in reference frame 3100referred to as an a-plane, a b-plane, and a c-plane, where: the a-planeis formed by the b-axis and the c-axis and is perpendicular to thea-axis; the b-plane is formed by the a-axis and the c-axis and isperpendicular to the b-axis; and the c-plane is formed by the a-axis andthe b-axis and is perpendicular to the c-axis. For purposes of thisdescription: reference to the a-plane includes the a-plane and any planeparallel thereto; reference to the b-plane includes the b-plane and anyplane parallel thereto; and reference to the c-plane includes thec-plane and any plane parallel thereto. Further, with regard to various“faces” or “surfaces” of the crystalline structures described herein, aface parallel to the a-plane may sometimes be referred to as a “b-c”face; a face parallel to the b-plane may sometimes be referred to as an“a-c” face; and a face parallel to the c-plane may sometimes be referredto as a “a-b” face.

FIG. 1 illustrates a crystalline structure 100 of an exemplary HTSmaterial as viewed from a first perspective, namely, a perspectiveperpendicular to an “a-b” face of crystalline structure 100 and parallelto the c-axis thereof. FIG. 2 illustrates crystalline structure 100 asviewed from a second perspective, namely, a perspective perpendicular toa “b-c” face of crystalline structure 100 and parallel to the a-axisthereof. FIG. 22 illustrates additional depth (i.e., into the page) forcrystalline structure 100 of the exemplary HTS material. For purposes ofthis description, the exemplary HTS material illustrated in FIG. 1, FIG.2 and FIG. 22 is generally representative of various HTS materials. Insome implementations of the invention, the exemplary HTS material may bea representative of a family of superconducting materials referred to asmixed-valence copper-oxide perovskites. The mixed-valence copper-oxideperovskite materials include, but are not limited to, LaBaCuO_(x), LSCO(e.g., La_(2-x)Sr_(x)CuO₄, etc.), YBCO (e.g., YBa₂Cu₃O₇, etc.), BSCCO(e.g., Bi₂Sr₂Ca₂Cu₃O₁₀, etc.), TBCCO (e.g., Tl₂Ba₂Ca₂Cu₃O₁₀ orTl_(m)Ba₂Ca_(n-1)Cu_(n)O_(2n+m+2+δ)), HgBa₂Ca₂Cu₃O_(x), and othermixed-valence copper-oxide perovskite materials. The other mixed-valencecopper-oxide perovskite materials may include, but are not limited to,various substitutions of the cations as would be appreciated. As wouldalso be appreciated, the aforementioned named mixed-valence copper-oxideperovskite materials may refer to generic classes of materials in whichmany different formulations exist. In some implementations of theinvention, the exemplary HTS materials may include an HTS materialoutside of the family of mixed-valence copper-oxide perovskite materials(“non-perovskite materials”). Further, in some implementations of theinvention, superconducting materials other than HTS materials may beused in accordance with various principles of the invention. Suchsuperconducting materials may include, but are not limited to, ironpnictides, magnesium diboride (MgB₂), and other superconductingmaterials. Other materials having an aperture 210 may be exploited inaccordance with various principles and/or aspects of the invention aswould be appreciated.

Many HTS materials have a structure similar to (though not necessarilyidentical to) that of crystalline structure 100 with different atoms,combinations of atoms, and/or lattice arrangements as would beappreciated. As illustrated in FIG. 2, crystalline structure 100 isdepicted with two complete unit cells of the exemplary HTS material,with one unit cell above reference line 110 and one unit cell belowreference line 110. FIG. 21 illustrates a single unit cell 2100 of theexemplary HTS material.

Generally speaking and as would be appreciated, a unit cell 2100 of theexemplary HTS material includes six “faces”: two “a-b” faces that areparallel to the c-plane; two “a-c” faces that are parallel to theb-plane; and two “b-c” faces that are parallel to the a-plane (see,e.g., FIG. 31). As would also be appreciated, a “surface” of HTSmaterial in the macro sense may be comprised of multiple unit cells 2100(e.g., hundreds, thousands or more). Reference in this description to a“surface” or “face” of the HTS material being parallel to a particularplane (e.g., the a-plane, the b-plane or the c-plane) indicates that thesurface is formed predominately (i.e., a vast majority) of faces of unitcell 2100 that are substantially parallel to the particular plane.Furthermore, reference in this description to a “surface” or “face” ofthe HTS material being parallel to planes other than the a-plane, theb-plane, or the c-plane (e.g., an ab-plane as described below, etc.)indicates that the surface is formed from some mixture of faces of unitcell 2100 that, in the aggregate macro sense, form a surfacesubstantially parallel to such other planes.

Studies indicate that some superconducting materials, including HTSmaterials, demonstrate an anisotropic (i.e., directional) dependence ofthe resistance phenomenon. In other words, resistance at a giventemperature and current density depends upon a direction in relation tocrystalline structure 100. For example, in their superconducting state,some superconducting materials can carry significantly more current, atzero resistance, in the direction of the a-axis and/or in the directionof the b-axis than such materials do in the direction of the c-axis. Aswould be appreciated, various superconducting materials exhibitanisotropy in various performance phenomenon, including the resistancephenomenon, in directions other than, in addition to, or as combinationsof those described above. For purposes of this description, reference toa material that tends to exhibit the resistance phenomenon (and similarlanguage) in a first direction indicates that the material supports suchphenomenon in the first direction; and reference to a material thattends not to exhibit the resistance phenomenon (and similar language) ina second direction indicates that the material does not support suchphenomenon in the second direction or does so in a reduced manner fromother directions.

Conventional understanding of known HTS materials has thus far failed toappreciate an aperture 210 formed within crystalline structure 100 by aplurality of aperture atoms 250 as being responsible for the resistancephenomenon. (See e.g., FIG. 21, where aperture 210 is not readilyapparent in a depiction of single unit cell 2100.) As will be furtherdescribed below, aperture 210 exists in many known HTS materials. Insome sense, aperture atoms 250 may be viewed as forming a discreteatomic “boundary” or “perimeter” around aperture 210. In someimplementations of the invention and as illustrated in FIG. 2, aperture210 appears between a first portion 220 and a second portion 230 ofcrystalline structure 100 although in some implementations of theinvention, aperture 210 may appear in other portions of various othercrystalline structures. While aperture 210, aperture 310, and otherapertures are illustrated in FIG. 2, FIG. 3, and elsewhere in thedrawings based on depictions of atoms as simple “spheres,” it would beappreciated that such apertures are related to and shaped by, amongother things, electrons and their associated electron densities (nototherwise illustrated) of various atoms in crystalline structure 100,including aperture atoms 250.

According to various aspects of the invention, aperture 210 facilitatespropagation of electrical charge through crystalline structure 100 andwhen aperture 210 facilitates propagation of electrical charge throughcrystalline structure 100, HTS material operates in its superconductingstate. For purposes of this description, “propagates,” “propagating,”and/or “facilitating propagation” (along with their respective forms)generally refer to “conducts,” “conducting” and/or “facilitatingconduction” and their respective forms; “transports,” “transporting”and/or “facilitating transport” and their respective forms; “guides,”“guiding” and/or “facilitating guidance” and their respective forms;and/or “carry,” “carrying” and/or “facilitating carrying” and theirrespective forms. For purposes of this description, electrical chargemay include positive charge or negative charge, and/or pairs or othergroupings of such charges. For purposes of this description, currentcarriers may include, but are not limited to, electrons. In someimplementations of the invention, aperture 210 propagates negativecharges through crystalline structure 100. In some implementations ofthe invention, aperture 210 propagates positive charges throughcrystalline structure 100. In some implementations of the invention,aperture 210 propagates pairs or other groupings of electrical chargethrough crystalline structure 100. In some implementations of theinvention, aperture 210 propagates current carriers through crystallinestructure 100. In some implementations of the invention, aperture 210propagates pairs or other groupings of current carriers throughcrystalline structure 100. In some implementations of the invention,aperture 210 propagates electrical charge in the form of one or moreparticles through crystalline structure 100. In some implementations ofthe invention, aperture 210 propagates electrons, pairs of electrons,and/or groupings of electrons in the form of one or more particlesthrough crystalline structure 100. In some implementations of theinvention, aperture 210 propagates electrical charge in the form of oneor more waves or wave packets through crystalline structure 100. In someimplementations of the invention, aperture 210 propagates electrons,pairs of electrons, and/or groupings of electrons in the form of one ormore waves or wave packets through crystalline structure 100.

In some implementations of the invention, propagation of electricalcharge through crystalline structure 100 may be in a manner analogous tothat of a waveguide. In some implementations of the invention, aperture210 may be a waveguide with regard to propagating electrical chargethrough crystalline structure 100. Waveguides and their operation aregenerally well understood. In particular, walls surrounding an interiorof the waveguide may correspond to the boundary or perimeter of apertureatoms 250 around aperture 210. One aspect relevant to an operation of awaveguide is its cross-section. Typically, the cross-section of awaveguide is related to a wavelength of the signals capable ofpropagating through the waveguide. Accordingly, the wavelength of theelectrical charge propagating through aperture 210 may be related to thecross-section of aperture 210. At the atomic level, aperture 210 and/orits cross-section may change substantially with changes in temperatureof the HTS material. For example, in some implementations of theinvention, changes in temperature of the HTS material may cause changesin aperture 210 and its operating characteristics, which in turn maycause the HTS material to transition between its superconducting stateto its non-superconducting state. In some implementations of theinvention, as temperature of the HTS material increases, aperture 210may restrict or impede propagation of electrical charge throughcrystalline structure 100 and the corresponding HTS material maytransition from its superconducting state to its non-superconductingstate. In some implementations of the invention, as temperature of theHTS material increases, the cross-section of aperture 210 may change,thereby inhibiting operation of aperture 210 in a manner analogous to awaveguide and the corresponding HTS material may transition from itssuperconducting state to its non-superconducting state. Likewise astemperature of the HTS material decreases, in some implementations ofthe invention, aperture 210 may facilitate (as opposed to restrict orimpede) propagation of electrical charge through crystalline structure100 and the corresponding HTS material may transition from itsnon-superconducting state to its superconducting state. In someimplementations of the invention, the cross-section of aperture 210 maychange, thereby facilitating operation of aperture 210 as a waveguide(or in a manner analogous thereto) and the corresponding HTS materialmay transition from its non-superconducting state to its superconductingstate.

According to various implementations of the invention, as long asaperture 210 is “maintained” within a given HTS material, the HTSmaterial should operate in a superconducting state. In variousimplementations of the invention, as long as aperture 210 is maintainedwithin a given HTS material, aperture 210 should operate in asuperconducting state. In various implementations of the invention,maintaining aperture 210 may include: maintaining aperture 210 in asuperconducting state; maintaining an ability of aperture 210 topropagate electrical charge through crystalline structure 100 in asuperconducting state; maintaining aperture atoms 250 relative to oneanother so that HTS material operates in a superconducting state;maintaining aperture atoms 250 with respect to other atoms withincrystalline structure 100 so that the HTS material operates in asuperconducting state; maintaining a cross-section of aperture 210sufficient to propagate electrical charge there through so that the HTSmaterial remains in a superconducting state; maintaining a cross-sectionof aperture 210 such that it does not impede, restrict, or otherwiseinterfere with the propagation of electrical charge so that the HTSmaterial remains in a superconducting state; maintaining a cross-sectionof aperture 210 sufficient to propagate current carriers there throughso that HTS material remains in a superconducting state; maintaining across-section of aperture 210 such that it does not interfere withcurrent carriers so that the HTS material remains in a superconductingstate; maintaining aperture 210 substantially free from obstruction sothat the HTS material remains in a superconducting state; maintainingaperture 210 so that HTS material operates with improved operatingcharacteristics; enhancing aperture 210 so that the HTS materialoperates in a superconducting state with improved operatingcharacteristics; enhancing aperture 210 so that the enhanced apertureoperates in a superconducting state with improved operatingcharacteristics; and/or other ways of maintaining aperture 210 such thatHTS material operates in a superconducting state. According to variousimplementations of the invention, maintaining aperture 210 withinexisting HTS materials may improve the operating characteristics ofthese existing HTS materials. According to various implementations ofthe invention, maintaining an aperture 210 within new materials mayresult in new HTS materials, some of which may have improved operatingcharacteristics over existing HTS materials. According to variousimplementations of the invention, as long as aperture 210 is maintainedwithin a given HTS material as temperature increases, the HTS materialshould operate in a superconducting state. According to variousimplementations of the invention, as long as aperture 210 is maintainedso as to propagate electrical charge through crystalline structure 100,the HTS material should operate in a superconducting state. According tovarious implementations of the invention, as long as aperture 210 ismaintained so as to propagate current carriers through crystallinestructure 100, the HTS material should operate in a superconductingstate. According to various implementations of the invention, as long asaperture atoms 250 are maintained relative to one another within a givenHTS material, the HTS material should operate in a superconductingstate. According to various implementations of the invention, as long asaperture atoms 250 are maintained relative to other atoms withincrystalline structure 100 within a given HTS material, the HTS materialshould operate in a superconducting state. According to variousimplementations of the invention, as long as a cross-section of aperture210 is maintained sufficient to propagate electrical charge throughaperture 210 within a given HTS material, the HTS material shouldoperate in a superconducting state. According to various implementationsof the invention, as long as a cross-section of aperture 210 ismaintained sufficient to propagate current carriers through aperture 210within a given HTS material, the HTS material should operate in asuperconducting state. According to various implementations of theinvention, as long as a cross-section of aperture 210 is maintained suchthat electrical charge receives little or no interference throughaperture 210, the HTS material should operate in a superconductingstate. According to various implementations of the invention, as long asa cross-section of aperture 210 is maintained such that current carriersreceive little or no interference through aperture 210, the HTS materialshould operate in a superconducting state. According to variousimplementations of the invention, as long as a cross-section of aperture210 is maintained substantially free from obstruction within a given HTSmaterial, the HTS material should operate in a superconducting state.

According to various implementations of the invention, aperture 210 maybe maintained, and/or designed to be maintained, such that aperture 210propagates electrical charge there through with little or nointerference. In some implementations of the invention, electricalcharge propagating through aperture 210 collides elastically with theboundary or “walls” of aperture 210 similar to the way reflection occursin an optical waveguide. More particularly, electrical chargepropagating through aperture 210 collides elastically with variousaperture atoms 250 that comprise the boundary or walls of aperture 210.As long as such collisions are elastic, the electrical charge willexperience minimal loss (i.e., “resistance”) as it propagates throughaperture 210.

Apertures, such as, but not limited to, aperture 210 in FIG. 2, exist invarious HTS materials, such as, but not limited to, various HTSmaterials illustrated in FIG. 3, FIG. 17, FIG. 18, FIG. 19, and varioussuperconducting materials, such as, but not limited to, varioussuperconducting materials illustrated in FIG. 32 and FIG. 33, anddescribed below. As illustrated, such apertures are intrinsic to thecrystalline structure of some or all the HTS materials. Various forms,shapes, sizes, and numbers of apertures 210 exist in HTS materialsdepending on the precise configuration of the crystalline structure,composition of atoms, and arrangement of atoms within the crystallinestructure of the HTS material as would be appreciated in light of thisdescription.

The presence and absence of apertures 210 that extend in the directionof various axes through the crystalline structures 100 of various HTSmaterials is consistent with the anisotropic dependence demonstrated bysuch HTS materials. For example, as will be discussed in further detailbelow, various HTS materials illustrated in FIG. 3, FIG. 17, FIG. 18,FIG. 19 and various superconducting materials illustrated in FIG. 45 andFIG. 46, have apertures that extend in the directions in which thesematerials demonstrate the resistance phenomenon; similarly, these HTSmaterials tend not to have apertures that extend in the directions inwhich these materials do not demonstrate the resistance phenomenon. Forexample, YBCO-123 exhibits the resistance phenomenon in the direction ofthe a-axis and the b-axis, but tends not to exhibit the resistancephenomenon in the direction of the c-axis. HTS material 360 which isillustrated in FIG. 3, FIG. 11, and FIG. 30 corresponds to YBCO-123.Consistent with the anisotropic dependence of the resistance phenomenondemonstrated by YBCO-123, FIG. 3 illustrates that apertures 310 extendthrough crystalline structure 300 in the direction of the a-axis; FIG.30 illustrates that apertures 310 and apertures 3010 extend throughcrystalline structure 300 in the direction of the b-axis; and FIG. 11illustrates that no suitable apertures extend through crystallinestructure 300 in the direction of the c-axis.

Aperture 210 and/or its cross-section may be dependent upon variousatomic characteristics of aperture atoms 250. Such atomiccharacteristics include, but are not limited to, atomic size, atomicweight, numbers of electrons, number of bonds, bond lengths, bondstrengths, bond angles between aperture atoms, bond angles betweenaperture atoms and non-aperture atoms, and/or isotope number. Apertureatoms 250 may be selected based on their corresponding atomiccharacteristic to optimize aperture 210 in terms of its size, shape,rigidity, and modes of vibration (in terms of amplitude, frequency, anddirection) in relation to crystalline structure and/or atoms therein.

In some implementations of the invention, at least some of apertureatoms 250 include atoms having high electro-negativity, for example, butnot limited to, oxygen. In some implementations of the invention, atleast some of aperture atoms 250 include atoms of an element understoodas having some degree of conductivity in their bulk form. In someimplementations of the invention, some of aperture atoms 250 includeatoms having high electro-negativity and some others of aperture atoms250 include atoms of an element understood as having some degree ofconductivity. In some implementations of the invention, aperture atoms250 may provide a source of electrical charge (e.g., electrons, etc.)that propagates through aperture 210. In some implementations of theinvention, aperture atoms 250 may provide a readily available source ofelectrical charge for flow of such electrical charge to occur throughaperture 210.

Aperture 210 and/or its cross-section may be dependent upon variousatomic characteristics of “non-aperture atoms” (i.e., atoms incrystalline structure 100 other than aperture atoms 250). Such atomiccharacteristics include, but are not limited to, atomic size, atomicweight, numbers of electrons, electronic structure, number of bonds,types of bonds, differing bonds, multiple bonds, bond lengths, bondstrengths, and/or isotope number. The non-aperture atoms may also beselected based on their corresponding atomic characteristics to optimizeaperture 210 in terms of its size, shape, rigidity, and their modes ofvibration (in terms of amplitude, frequency, and direction) in relationto crystalline structure and/or atoms therein. In some implementationsof the invention, non-aperture atoms may provide a source of electricalcharge (e.g., electrons, etc.) that propagates through aperture 210. Insome implementations of the invention, non-aperture atoms may provide areadily available source of electrical charge for flow of suchelectrical charge to occur through aperture 210.

In some implementations of the invention, aperture 210 may be dependentupon various atomic characteristics of non-aperture atoms in relation toaperture atoms 250. In some implementations of the invention, aperture210 may be dependent upon various atomic characteristics of apertureatoms 250 in relation to non-aperture atoms. In some implementations ofthe invention, aperture 210 may be dependent upon various atomiccharacteristics of aperture atoms 250 in relation to other apertureatoms 250. In some implementations of the invention, aperture 210 may bedependent upon various atomic characteristics of non-aperture atoms inrelation to other non-aperture atoms.

According to various implementations of the invention, changes toaperture 210 within crystalline structure 110 may have an impact on theresistance phenomenon. According to various implementations of theinvention, changes to the cross-section of aperture 210 may have animpact on the resistance phenomenon. According to variousimplementations of the invention, changes to obstructions withinaperture 210, including changes to a size of the obstruction, a numberof the obstructions, or a frequency or probability with which suchobstructions appear, may have an impact on the resistance phenomenon. Insome implementations of the invention, such obstructions may bedependent upon various atomic characteristics of aperture atoms 250. Insome implementations of the invention, such obstructions may bedependent upon various atomic characteristics of non-aperture atoms.Atomic characteristics include, but are not limited to, atomic size,atomic weight, numbers of electrons, electronic structure, number ofbonds, types of bonds, differing bonds, multiple bonds, bond lengths,bond strengths, and/or isotope number.

According to various implementations of the invention, changes in aphysical structure of aperture 210, including changes to a shape and/orsize of its cross-section, may have an impact on the resistancephenomenon. According to various implementations of the invention,changes in an electronic structure of aperture 210 may have an impact onthe resistance phenomenon. According to various implementations of theinvention, changes in crystalline structure 100 that affect apertureatoms 250 may have an impact on the resistance phenomenon. Changesaffecting aperture atoms 250 may include, but are not limited to: 1)displacement of a nucleus of an aperture atom relative to other apertureatoms; 2) displacement of a nucleus of a non-aperture atom relative toaperture atoms; 3) changing possible energy states of aperture and/ornon-aperture atoms; and 4) changing occupancy of such possible energystates. Any of such changes or combinations of such changes may affectaperture 210. For example, as temperature of crystalline structure 100increases, the cross-section of aperture 210 may be changed due tovibration of various atoms within crystalline structure 100 as well aschanges in energy states, or occupancy thereof, of the atoms incrystalline structure 100. Physical flexure, tension or compression ofcrystalline structure 100 may also affect the positions of various atomswithin crystalline structure 100 and therefore the cross-section ofaperture 210. Magnetic fields imposed on crystalline structure 100 mayalso affect the positions of various atoms within crystalline structure100 and therefore the cross-section of aperture 210.

Phonons correspond to various modes of vibration within crystallinestructure 100. Phonons in crystalline structure 100 may interact withelectrical charge propagated through crystalline structure 100. Moreparticularly, phonons in crystalline structure 100 may cause atoms incrystalline structure 100 (e.g., aperture atoms 250, non-aperture atoms,etc.) to interact with electrical charge propagated through crystallinestructure 100. Higher temperatures result in higher phonon amplitude andmay result in increased interaction among phonons, atoms in crystallinestructure 100, and such electrical charge. Various implementations ofthe invention may minimize, reduce, or otherwise modify such interactionamong phonons, atoms in crystalline structure 100, and such electricalcharge within crystalline structure 100.

In some implementations of the invention, modifications to crystallinestructure 100 of an existing HTS material may be made to maintainaperture 210 within crystalline structure 100 thereby permitting theexisting HTS material to operate with improved operatingcharacteristics. In some implementations of the invention, modificationsto crystalline structure 100 of an existing HTS material may be made tomaintain aperture 210 within crystalline structure 100 at highertemperatures thereby permitting the existing HTS material to operatewith improved operating characteristics. In some implementations of theinvention, modifications to crystalline structure 100 of the existingHTS material may be made to maintain aperture 210 within crystallinestructure 100 at higher temperatures thereby permitting the existing HTSmaterial to remain in a superconducting state at higher temperaturesand/or with increased current capacity and/or with other improvedoperational characteristics. In some implementations of the invention,new HTS materials may be designed with crystalline structures that formand maintain aperture 210 at higher temperatures and/or with increasedcurrent capacity and/or with other improved operational characteristics.Various mechanisms may be used to modify crystalline structure 100 inorder to maintain aperture 210.

In some implementations of the invention, aperture 210 is maintained attemperatures at, about, or above that of liquid nitrogen. In someimplementations of the invention, aperture 210 is maintained attemperatures at, about, or above that of solid carbon dioxide. In someimplementations of the invention, aperture 210 is maintained attemperatures at, about, or above that of liquid ammonia. In someimplementations of the invention, aperture 210 is maintained attemperatures at, about, or above that of various formulations of liquidFreon. In some implementations of the invention, aperture 210 ismaintained at temperatures at, about, or above that of frozen water. Insome implementations of the invention, aperture 210 is maintained attemperatures at, about, or above that of room temperature (e.g., 21°C.).

Accordingly, various new HTS materials may be created, either asmodifications of existing HTS materials or design and formation of newHTS materials. In some implementations of the invention, an HTS materialoperates in a superconducting state at temperatures at, about, or abovethat of liquid nitrogen. In some implementations of the invention, anHTS material operates in a superconducting state at temperatures at,about, or above that of solid carbon dioxide. In some implementations ofthe invention, an HTS material operates in a superconducting state attemperatures at, about, or above that of liquid ammonia. In someimplementations of the invention, an HTS material operates in asuperconducting state temperatures at, about, or above that of variousformulations of liquid Freon. In some implementations of the invention,an HTS material operates in a superconducting state at temperatures at,about, or above that of frozen water. In some implementations of theinvention, an HTS material operates in a superconducting state attemperatures at, about, or above that of room temperature (e.g., 21°C.). In some implementations of the invention, portions of the HTSmaterial operates in the superconducting state at, about, or above anyone or more of these temperatures.

FIG. 3 illustrates a crystalline structure 300 of an exemplary HTSmaterial 360 from a second perspective. Exemplary HTS material 360 is asuperconducting material commonly referred to as “YBCO” which, incertain formulations, has a transition temperature of approximately 90K.In particular, exemplary HTS material 360 depicted in FIG. 3 isYBCO-123. Crystalline structure 300 of exemplary HTS material 360includes various atoms of yttrium (“Y”), barium (“Ba”), copper (“Cu”)and oxygen (“O”). As illustrated in FIG. 3, an aperture 310 is formedwithin crystalline structure 300 by aperture atoms 350, namely atoms ofyttrium, copper, and oxygen. A cross-sectional distance between theyttrium aperture atoms in aperture 310 is approximately 0.389 nm, across-sectional distance between the oxygen aperture atoms in aperture310 is approximately 0.285 nm, and a cross-sectional distance betweenthe copper aperture atoms in aperture 310 is approximately 0.339 nm.

FIG. 30 illustrates crystalline structure 300 of exemplary HTS material360 from a third perspective. Similar to that described above withregard to FIG. 3, exemplary HTS material 360 is YBCO-123, and aperture310 is formed within crystalline structure 300 by aperture atoms 350,namely atoms of yttrium, copper, and oxygen. In this orientation, across-sectional distance between the yttrium aperture atoms in aperture310 is approximately 0.382 nm, a cross-sectional distance between theoxygen aperture atoms in aperture 310 is approximately 0.288 nm, and across-sectional distance between the copper aperture atoms in aperture310 is approximately 0.339 nm. In this orientation, in addition toaperture 310, crystalline structure 300 of exemplary HTS material 360includes an aperture 3010. Aperture 3010 occurs in the direction of theb-axis of crystalline structure 300. More particularly, aperture 3010occurs between individual unit cells of exemplary HTS material 360 incrystalline structure 300. Aperture 3010 is formed within crystallinestructure 300 by aperture atoms 3050, namely atoms of barium, copper andoxygen. A cross-sectional distance between the barium aperture atoms3050 in aperture 3010 is approximately 0.430 nm, a cross-sectionaldistance between the oxygen aperture atoms 3050 in aperture 3010 isapproximately 0.382 nm, and a cross-sectional distance between thecopper aperture atoms 3050 in aperture 3010 is approximately 0.382 nm.In some implementations of the invention, aperture 3010 operates in amanner similar to that described herein with regard to aperture 310. Forpurposes of this description, aperture 310 in YBCO may be referred to asan “yttrium aperture,” whereas aperture 3010 in YBCO may be referred toas a “barium aperture,” based on the compositions of their respectiveaperture atoms 350, 3050.

FIG. 17 illustrates a crystalline structure 1700 of an exemplary HTSmaterial 1760 as viewed from the second perspective. Exemplary HTSmaterial 1760 is an HTS material commonly referred to as “HgBa₂CuO₄”which has a transition temperature of approximately 94K. Crystallinestructure 1700 of exemplary HTS material 1760 includes various atoms ofmercury (“Hg”), barium (“Ba”), copper (“Cu”), and oxygen (“O”). Asillustrated in FIG. 17, an aperture 1710 is formed within crystallinestructure 1700 by aperture atoms which comprise atoms of barium, copper,and oxygen.

FIG. 18 illustrates a crystalline structure 1800 of an exemplary HTSmaterial 1860 as viewed from the second perspective. Exemplary HTSmaterial 1860 is an HTS material commonly referred to as“TI₂Ca₂Ba₂Cu₃O₁₀” which has a transition temperature of approximately128K. Crystalline structure 1800 of exemplary HTS material 1860 includesvarious atoms of thallium (“TI”), calcium (“Ca”), barium (“Ba”), copper(“Cu”), and oxygen (“O”). As illustrated in FIG. 18, an aperture 1810 isformed within crystalline structure 1800 by aperture atoms whichcomprise atoms of calcium, barium, copper and oxygen. As alsoillustrated in FIG. 18, a secondary aperture 1820 may also be formedwithin crystalline structure 1800 by secondary aperture atoms whichcomprise atoms of calcium, copper and oxygen. Secondary apertures 1820may operate in a manner similar to that of apertures 1810.

FIG. 19 illustrates a crystalline structure 1900 of an exemplary HTSmaterial 1960 as viewed from the second perspective. Exemplary HTSmaterial 1960 is an HTS material commonly referred to as “La₂CuO₄” whichhas a transition temperature of approximately 39K. Crystalline structure1900 of exemplary HTS material 1960 includes various atoms of lanthanum(“La”), copper (“Cu”), and oxygen (“O”). As illustrated in FIG. 19, anaperture 1910 is formed within crystalline structure 1900 by apertureatoms which comprise atoms of lanthanum and oxygen.

FIG. 45 illustrates a crystalline structure 4500 of an material from abroader class of superconducting materials (i.e., other than an HTSmaterial) as viewed from the second perspective. Exemplarysuperconducting material 4560 is a superconducting material commonlyreferred to as “As₂Ba_(0.34)Fe₂K_(0.66)” which has a transitiontemperature of approximately 38K. Exemplary superconducting material4560 is representative of a family of superconducting materialssometimes referred to as “iron pnictides.”

Crystalline structure 4500 of exemplary superconducting material 4560includes various atoms of arsenic (“As”), barium (“Ba”), iron (“Fe”),and potassium (“K”). As illustrated in FIG. 45, an aperture 4510 isformed within crystalline structure 4500 by aperture atoms whichcomprise atoms of potassium and arsenic.

FIG. 46 illustrates a crystalline structure 4600 of a material from thebroader class of superconducting materials (i.e., other than an HTSmaterial) as viewed from the second perspective. Exemplarysuperconducting material 4660 is a superconducting material commonlyreferred to as “MgB₂” which has a transition temperature ofapproximately 39K. Crystalline structure 4600 of exemplarysuperconducting material 4660 includes various atoms of magnesium (“Mg”)and boron (“B”). As illustrated in FIG. 46, an aperture 4610 is formedwithin crystalline structure 4600 by aperture atoms which comprise atomsof magnesium and boron.

The foregoing exemplary HTS materials illustrated in FIG. 3, FIG. 17,FIG. 18, FIG. 19, and FIG. 30, and the foregoing exemplarysuperconducting materials illustrated in FIG. 45 and FIG. 46, eachdemonstrate the presence of various apertures within suchsuperconducting materials. Various other superconducting materials,including HTS materials, have similar apertures. Once attributed to theresistance phenomenon, apertures and their corresponding crystallinestructures may be exploited to improve operating characteristics ofexisting superconducting materials, to derive improved superconductingmaterials from existing superconducting materials, and/or to design andformulate new superconducting materials.

In some implementations of the invention, apertures and theircrystalline structures may be modeled, using various computer modelingtools, to improve operating characteristics of various HTS materials.For convenience of description, HTS material 360 (and its attendantcharacteristics and structures) henceforth generally refers to variousHTS materials, including, but not limited to, HTS material 1760, HTSmaterial 1860 and other HTS materials illustrated in the drawings, notjust that HTS material illustrated and described with reference to FIG.3.

FIG. 4 illustrates a conceptual mechanical model 400 of crystallinestructure 100. Conceptual model 400 includes three springs, namely, aspring S₁, a spring S_(F), and a spring S₂, and two masses, namely amass M₁ and a mass M₂. For purposes of this description, spring S₁ maybe modeled as attached to a rigid wall 410 on one side and mass M₁ onthe other. Together spring S₁ and mass M₁ may be used to model firstportion 220 of crystalline structure 100. Mass M₁ is coupled betweenspring S₁ and spring S_(F). Spring S_(F) may be used to model aperture210 of crystalline structure 100 (i.e., the forces interacting betweenfirst portion 220 and second portion 230). Spring S_(F) is coupledbetween mass M₁ and mass M₂. Mass M₂ is coupled between spring S_(F) andspring S₂. Together spring S₂ and mass M₂ may be used to model secondportion 230 of crystalline structure 100. Again, for purposes of thisdescription, spring S₂ may be modeled as attached to a rigid wall 420.Other crystalline structures may be modeled as would be apparent.

The springs in FIG. 4 represent the forces interacting between groups ofatoms within crystalline structure 100. Each of these forces may bemodeled with a spring according to well-established modeling techniques.While the springs in FIG. 4 are depicted in a single dimension, itshould be appreciated that the springs may be modeled inthree-dimensions as would be apparent; however, such three-dimensionaldepiction is not necessary for purposes of understanding the inventionor implementations thereof.

As would be appreciated, temperature and vibrations of atoms (e.g.,phonons) are related. In particular, temperature of the HTS materialincreases as vibrations of the atoms of the HTS materials increase.Amplitude and frequency of these vibrations are related to variousforces and masses present in a given HTS material. With regard tocrystalline structure 100, springs S₁, S₂, and S_(F) and masses M₁ andM₂ affect the vibrations of the mechanical model which in turn simulatethe vibrations experienced by crystalline structure 100 as temperatureincreases, which may in turn impact aperture 210.

According to various implementations of the invention, these vibrationsaffect aperture 210. According to various implementations of theinvention, at temperatures above the transition temperature, thevibrations change or otherwise affect aperture 210 such that the HTSmaterial operates in its non-superconducting state (e.g., thecross-section of aperture 210 restricts, impedes, or otherwise does notfacilitate the propagation of electrical charge through aperture 210);whereas, at temperatures below the transition temperature, thevibrations do not prevent the HTS material from operating in itssuperconducting state (e.g., the cross-section of aperture 210facilitates propagation of electrical charge through aperture 210).

According to various implementations of the invention, at temperaturesabove the transition temperature, the vibrations change or otherwiseaffect aperture atoms 250 such that the HTS material transitions toand/or operates in its non-superconducting state (or in other words,ceases to operate in its superconducting state). According to variousimplementations of the invention, at temperatures above the transitiontemperature, the vibrations change or otherwise affect non-apertureatoms such that the HTS material transitions to and/or operates in itsnon-superconducting state.

According to various implementations of the invention, the crystallinestructure of various known HTS materials may be modified (therebyproducing new material derivations) such that the modified HTS materialoperates with improved operating characteristics over the known HTSmaterial. According to various implementations of the invention, thecrystalline structure of various known HTS materials may be modifiedsuch that aperture 210 is maintained at higher temperatures. Accordingto various implementations of the invention, the crystalline structureof various known HTS materials may be modified (thereby producing newHTS material derivations) such that aperture 210 propagates electricalcharge at higher temperatures. According to various implementations ofthe invention, the crystalline structure of various new and previouslyunknown HTS materials may be designed and fabricated such that the newHTS materials operate with improved operating characteristics overexisting HTS materials. According to various implementations of theinvention, the crystalline structure of various new and previouslyunknown HTS materials may be designed and fabricated such that aperture210 is maintained at higher temperatures. According to variousimplementations of the invention, the crystalline structure of variousnew and previously unknown HTS materials may be designed and fabricatedsuch that aperture 210 propagates electrical charge at highertemperatures.

According to various implementations of the invention, apertures 210 incrystalline structure 100 have a cross-section of sufficient size topropagate electric charge through crystalline structure 100 so that HTSmaterial 360 operates in a superconducting state. In someimplementations of the invention, those apertures 210 in crystallinestructure 100 having a cross-section ranging in size from 0.20 nm to1.00 nm may propagate electric charge through crystalline structure 100so that HTS material 360 operates in a superconducting state. Accordingto various implementations of the invention, apertures 210 incrystalline structure 100 have a cross-section of sufficient size topropagate electric charge through crystalline structure 100 so thataperture 210 operates in a superconducting state. In someimplementations, those apertures 210 in crystalline structure 100 havinga cross-section ranging in size from 0.20 nm to 1.00 nm may propagateelectric charge through crystalline structure 100 so that aperture 210operates in a superconducting state.

In some implementations of the invention, improving and designing an HTSmaterial that operates with improved operating characteristics mayinvolve analyzing mechanical aspects (e.g., forces, distances, masses,modes of vibration, etc.) of aperture 210 and crystalline structure 100so that aperture 210 is maintained sufficiently to remain in asuperconducting state at higher temperatures. In some implementations ofthe invention, improving and designing HTS materials that operate withimproved operating characteristics may involve analyzing electronicaspects (e.g., attractive and repulsive atomic forces, conductivity,electro-negativity, etc.) of atoms in crystalline structure 100(including, but not limited to aperture atoms 250) so that aperture 210is maintained sufficiently to remain in a superconducting state athigher temperatures. In some implementations of the invention, improvingand designing HTS materials that operate with improved operatingcharacteristics may involve analyzing both electrical aspects andmechanical aspects of aperture 210 and crystalline structure 100, andthe atoms therein, so that aperture 210 is maintained sufficiently tooperate in a superconducting state at higher temperatures.

In some implementations of the invention, conceptually speaking, aspring constant of spring S₁ may be changed such that S₁′≠S₁ asillustrated in FIG. 5. A changed spring constant tends to change theamplitude, modes, frequency, direction, and/or other vibrationalcharacteristics of vibrations of the mechanical model. The changedspring constant may guide a corresponding change in crystallinestructure 100, for example, a change to a rigidity of first portion 220of crystalline structure 100. The rigidity of first portion 220 ofcrystalline structure 100 may be changed by changing various atomswithin first portion 220 to affect bond lengths, bond strengths, bondangles, number of bonds or other atomic characteristics of atoms withinfirst portion 220. The rigidity of first portion 220 of crystallinestructure 100 may be changed by bonding fewer or more atoms to firstportion 220 thereby effectively changing the spring constant of springS₁ as would be appreciated.

In some implementations of the invention, conceptually speaking, aspring constant of spring S₂ may be changed such that S₂≠S₂ asillustrated in FIG. 6. As described above, a changed spring constanttends to change the amplitude, modes, frequency, direction, and/or othervibrational characteristics of vibrations of the mechanical model. Thechanged spring constant may guide a corresponding change in crystallinestructure 100, for example, a change to a rigidity of second portion 230of crystalline structure 100 in a manner similar to that described abovewith regard to spring S₁. The rigidity of second portion 230 ofcrystalline structure 100 may be changed by bonding fewer or more atomsto second portion 230 thereby effectively changing the spring constantof spring S₂ as would be appreciated.

In some implementations of the invention, again, conceptually speaking,a spring constant of spring S_(F) may be changed such that S_(F)′≠S_(F)as illustrated in FIG. 7. As described above, a changed spring constanttends to change the amplitude, modes, frequency, direction, and/or othervibrational characteristics of vibrations of the mechanical model. Thechanged spring constant may guide a corresponding change in crystallinestructure 100, for example, a change to a rigidity of aperture 210formed within crystalline structure 100. This may be accomplished in avariety of ways including, but not limited to, changing a shape ofaperture 210 to one that is structurally different in strength thanother shapes, changing bond strengths between aperture atoms, changingbond angles, changing modes of vibration of crystalline structure 100,changing apertures atoms 250, or other ways. This may also beaccomplished, for example, by layering a material over crystallinestructure 100 such that atoms of the material span aperture 210 byforming one or more bonds between first portion 220 and second portion230 thereby effectively changing the spring constant of spring S_(F) aswould be appreciated. In other words, the atoms spanning aperture 210introduce an additional spring S in parallel with S_(F), that in effect,changes the spring constant between first portion 220 and second portion230. This modification of layering material over crystalline structure100 is described in further detail below in connection with variousexperimental test results.

In some implementations of the invention, again conceptually speaking, amass of mass M₁ may be decreased such that M₁′<M₁ as illustrated in FIG.8. A decreased mass tends to change various amplitude, modes, frequency,direction and/or other vibrational characteristics of vibrations of themechanical model. The decreased mass may guide a corresponding change incrystalline structure 100, which may ultimately lead to maintainingand/or stabilizing aperture 210 within crystalline structure 100 athigher temperatures. This may be accomplished by, for example, usingsmaller molecules and/or atoms within first portion 220 of crystallinestructure 100 or replacing various larger molecules and/or atoms withsmaller ones. Similar effects may be achieved by decreasing a mass ofmass M₂.

In some implementations of the invention, again conceptually speaking, amass of mass M₁ may be increased such that M₁′>M₁ as illustrated in FIG.9. An increased mass tends to change various amplitude, modes,frequency, direction and/or other vibrational characteristics ofvibrations of the mechanical model. The increased mass may guide acorresponding change in crystalline structure 100, which may ultimatelylead to maintaining and/or stabilizing aperture 210 within crystallinestructure 100 at higher temperatures. This may be accomplished by, forexample, using larger atoms within first portion 220 of crystallinestructure 100 or replacing various smaller atoms with larger ones.Similar effects may be achieved by increasing a mass of mass M₂.

In various implementations of the invention, any combination of thevarious changes described above with regard to FIGS. 5-9 may be made tochange vibrations of the mechanical model, which may guide correspondingchanges in crystalline structure 100 in order to maintain aperture 210at higher temperatures. In some implementations of the invention,tradeoffs between various changes may be necessary in order to provide anet improvement to the maintenance of aperture 210.

In some implementations of the invention, a three-dimensional computermodel of crystalline structure 100 may be used to design an HTS materialwith an appropriate aperture 210 that is maintained at highertemperatures. Such models may be used to analyze interactions betweenaperture atoms 250 and/or non-aperture atoms and their respective impacton aperture 210 over temperature as would be apparent. For example,various computer modeling tools may be used to visualize and analyzecrystalline structure 100, and in particular, visualize and analyzeapertures 210 in crystalline structure 100. One such computer modelingtool is referred to as “Jmol,” which is an open-source Java viewer forviewing and manipulating chemical structures in 3D. Jmol is available athttp://www.jmol.org.

In some implementations of the invention, various three-dimensionalcomputer models of crystalline structure 100 may be simulated todetermine and evaluate crystalline structures 100 and the interaction ofatoms therein. Such computer models may employ the density functionaltheory (“DFT”). Computer models employing DFT may be used to design newHTS materials and modify existing HTS materials based on maintainingaperture 210 so that these HTS materials operate in a superconductingstate in accordance with various principles of the invention describedherein and as would be appreciated.

In some implementations of the invention, combinations of the springsand masses may be selected to change vibrations (including theirassociated vibrational characteristics) that affect aperture 210 withincrystalline structure 100 according to various known techniques. Inother words, the springs and masses may be modified and/or selected tochange amplitude, modes, frequency, direction and/or other vibrationalcharacteristics of various vibrations within crystalline structure 100to minimize their impact on aperture 210. By way of example, the springsand masses may be modified and/or selected to permit vibrations withincrystalline structure 100 in directions parallel (or substantiallyparallel) to the propagation of electrical charge through aperture 210thereby reducing the impact of such vibrations on aperture 210. By wayof further example, the springs and masses may be modified and/orselected to adjust various resonant frequencies with crystallinestructure 100 to propagate electrical charge through aperture 210 atdifferent temperatures.

In some implementations of the invention, combinations of the springsand masses may be selected to maintain aperture 210 within crystallinestructure 100 regardless of vibrations experienced within crystallinestructure 100. In other words, reducing, increasing and/or otherwisechanging vibrations within crystalline structure 100 may not otherwiseimpact the resistance phenomenon provided that aperture 210 itself ismaintained.

FIG. 10 illustrates a modified crystalline structure 1010 of a modifiedHTS material 1060 as viewed from the second perspective in accordancewith various implementations of the invention. FIG. 11 illustratesmodified crystalline structure 1010 of modified HTS material 1060 asviewed from the first perspective in accordance with variousimplementations of the invention. HTS material 360 (e.g., for example,as illustrated in FIG. 3 and elsewhere) is modified to form modified HTSmaterial 1060. Modifying material 1020 forms bonds with atoms ofcrystalline structure 300 (of FIG. 3) of HTS material 360 to formmodified crystalline structure 1010 of modified HTS material 1060 asillustrated in FIG. 11. As illustrated, modifying material 1020 bridgesa gap between first portion 320 and second portion 330 thereby changing,among other things, vibration characteristics of modified crystallinestructure 1010, particularly in the region of aperture 310. In doing so,modifying material 1020 maintains aperture 310 at higher temperatures.In reference to FIG. 7, modifying material 1020 serves to modify theeffective spring constant of spring S_(F), by, for example, acting asone or more additional springs in parallel with spring S_(F).Accordingly, in some implementations of the invention, modifyingmaterial 1020 is specifically selected to fit in and bond withappropriate atoms in crystalline structure 300.

In some implementations of the invention and as illustrated in FIG. 10,modifying material 1020 is bonded a face of crystalline structure 300that is parallel to the b-plane (e.g., an “a-c” face). In suchimplementations where modifying material 1020 is bonded to the “a-c”face, apertures 310 extending in the direction of the a-axis and withcross-sections lying in the a-plane are maintained. In suchimplementations, charge carriers flow through aperture 310 in thedirection of the a-axis.

In some implementations of the invention, modifying material 1020 isbonded to a face of crystalline structure 300 that is parallel to thea-plane (e.g., a “b-c” face). In such implementations where modifyingmaterial 1020 is bonded to the “b-c” face, apertures 310 extending inthe direction of the b-axis and with cross-sections lying in the b-planeare maintained. In such implementations, charge carriers flow throughaperture 310 in the direction of the b-axis.

Various implementations of the invention include layering a particularsurface of HTS material 360 with modifying material 1020 (i.e.,modifying the particular surface of HTS material 360 with the modifyingmaterial 1020). As would be recognized from this description, referenceto “modifying a surface” of HTS material 360, ultimately includesmodifying a face (and in some cases more that one face) of one or moreunit cells 2100 of HTS material 360. In other words, modifying material1020 actually bonds to atoms in unit cell 2100 of HTS material 360.

For example, modifying a surface of HTS material 360 parallel to thea-plane includes modifying “b-c” faces of unit cells 2100. Likewise,modifying a surface of HTS material 360 parallel to the b-plane includesmodifying “a-c” faces of unit cells 2100. In some implementations of theinvention, modifying material 1020 is bonded to a surface of HTSmaterial 360 that is substantially parallel to any plane that isparallel to the c-axis. For purposes of this description, planes thatare parallel to the c-axis are referred to generally as ab-planes, andas would be appreciated, include the a-plane and the b-plane. As wouldbe appreciated, a surface of HTS material 360 parallel to the ab-planeis formed from some mixture of “a-c” faces and “b-c” faces of unit cells2100. In such implementations where modifying material 1020 is bonded toa surface parallel to an ab-plane, apertures 310 extending in thedirection of the a-axis and apertures 310 extending in the direction ofthe b-axis are maintained.

In some implementations of the invention, modifying material 1020 may bea conductive material. In some implementations of the invention,modifying material 1020 may a material with high oxygen affinity (i.e.,a material that bonds easily with oxygen) (“oxygen bonding material”).In some implementations of the invention, modifying material 1020 may bea conductive material that bonds easily with oxygen (“oxygen bondingconductive materials”). Such oxygen bonding conductive materials mayinclude, but are not limited to: chromium, copper, bismuth, cobalt,vanadium, and titanium. Such oxygen bonding conductive materials mayalso include, but are not limited to: rhodium or beryllium. Othermodifying materials may include gallium or selenium. In someimplementations of the invention, modifying material 1020 may bechromium (Cr). In some implementations of the invention, modifyingmaterial 1020 may be copper (Cu). In some implementations of theinvention, modifying material 1020 may be bismuth (Bi). In someimplementations of the invention, modifying material 1020 may be cobalt(Co). In some implementations of the invention, modifying material 1020may be vanadium (V). In some implementations of the invention, modifyingmaterial 1020 may be titanium (Ti). In some implementations of theinvention, modifying material 1020 may be rhodium (Rh). In someimplementations of the invention, modifying material 1020 may beberyllium (Be). In some implementations of the invention, modifyingmaterial 1020 may be gallium (Ga). In some implementations of theinvention, modifying material 1020 may be selenium (Se). In someimplementations of the invention, other elements may be used asmodifying material 1020. In some implementations of the invention,combinations of different materials (e.g., compounds, compositions,molecules, alloys, etc.) may be used as modifying material 1020. In someimplementations of the invention, various layers of materials and/orcombinations of materials may be used collectively as modifying material1020. In some implementations of the invention, modifying material 1020corresponds to atoms having appropriate bonding with oxygen. In someimplementations of the invention, modifying material 1020 includes atomsthat have bond lengths with various atom(s) in crystalline structure1010 at least as large as half the distance between atoms of firstportion 320 and atoms of second portion 330. In some implementations ofthe invention, modifying material 1020 includes atoms that bond withvarious atom(s) in crystalline structure 1010. In some implementationsof the invention, modifying material 1020 includes atoms that bond wellwith various atom(s) in crystalline structure 1010.

In some implementations of the invention, oxides of modifying material1020 may form during various operations associated with modifying HTSmaterial 360 with modifying material 1020. Accordingly, in someimplementations of the invention, modifying material 1020 may comprise asubstantially pure form of modifying material 1020 and various oxides ofmodifying material 1020. In other words, in some implementations of theinvention, HTS material 360 is modified with modifying material 1020 andvarious oxides of modifying material 1020. By way of example, but notlimitation, in some implementations of the invention, modifying material1020 may comprise chromium and chromium oxide (Cr_(x)O_(y)). In someimplementations of the invention, HTS material 360 is modified withvarious oxides of modifying material 1020. By way of example, but notlimitation, in some implementations of the invention, HTS material 360is modified with chromium oxide (Cr_(x)O_(y)).

In some implementations of the invention, other materials may be used tomodify crystalline structure 1010. For example, a modifying material1020 having increased bond strengths in relation to the copper oxidelayer may be selected to replace yttrium (one of the aperture atoms).Also for example, a modifying material 1020 having increased bondstrengths in relation to yttrium may be selected to replace the copperoxide layer. For example, chromium oxide (CrO) may be selected toreplace the copper oxide (CuO). Also for example, a modifying material1020 having increased bond strengths in relation to the copper oxidelayer may be selected to replace barium. While these examples refer tobond strengths, various modifying materials 1020 may be selected basedon other atomic characteristics or combinations thereof that tend tomaintain aperture 310 at higher temperatures, for example, but notlimited to, modifying materials 1020 that may result in net changes invibrations in crystalline structure 1010.

In some implementations of the invention, HTS material 360 may be YBCOand modifying material 1020 may be an oxygen bonding conductivematerial. In some implementations of the invention, modifying material1020 may be chromium and HTS material 360 may be YBCO. In someimplementations of the invention, modifying material 1020 may be copperand HTS material 360 may be YBCO. In some implementations of theinvention, modifying material 1020 may be bismuth and HTS material 360may be YBCO. In some implementations of the invention, modifyingmaterial 1020 may be cobalt and HTS material 360 may be YBCO. In someimplementations of the invention, modifying material 1020 may bevanadium and HTS material 360 may be YBCO. In some implementations ofthe invention, modifying material 1020 may be titanium and HTS material360 may be YBCO. In some implementations of the invention, modifyingmaterial 1020 may be rhodium and HTS material 360 may be YBCO. In someimplementations of the invention, modifying material 1020 may beberyllium and HTS material 360 may be YBCO. In some implementations ofthe invention, modifying material 1020 is another oxygen bondingconductive material and HTS material 360 may be YBCO.

In some implementations of the invention, modifying material 1020 may begallium and HTS material 360 may be YBCO. In some implementations of theinvention, modifying material 1020 may be selenium and HTS material 360may be YBCO.

In some implementations of the invention, various other combinations ofmixed-valence copper-oxide perovskite materials and oxygen bondingconductive materials may be used. For example, in some implementationsof the invention, HTS material 360 corresponds to a mixed-valencecopper-oxide perovskite material commonly referred to as “BSCCO.” BSCCOincludes various atoms of bismuth (“Bi”), strontium (“Sr”), calcium(“Ca”), copper (“Cu”) and oxygen (“O”). By itself, BSCCO has atransition temperature of approximately 100K. In some implementations ofthe invention, HTS material 360 may be BSCCO and modifying material 1020may be an oxygen bonding conductive material. In some implementations ofthe invention, HTS material 360 may be BSCCO and modifying material 1020may be selected from the group including, but not limited to: chromium,copper, bismuth, cobalt, vanadium, titanium, rhodium, or beryllium. Insome implementations of the invention, HTS material 360 may be BSCCO andmodifying material 1020 may be selected from the group consisting of:chromium, copper, bismuth, cobalt, vanadium, titanium, rhodium, andberyllium.

In some implementations of the invention, various combinations of othersuperconducting materials (i.e., rather than HTS material 360) andmodifying materials may be used. For example, in some implementations ofthe invention, the superconducting material corresponds to an ironpnictide material. Iron pnictides, by themselves, have transitiontemperatures that range from approximately 25-60K. In someimplementations of the invention, the superconducting material may be aniron pnictide and modifying material 1020 may be an oxygen bondingconductive material. In some implementations of the invention, thesuperconducting material may be an iron pnictide and modifying material1020 may be selected from the group including, but not limited to:chromium, copper, bismuth, cobalt, vanadium, titanium, rhodium, orberyllium. In some implementations of the invention, the superconductingmaterial may be an iron pnictide and modifying material 1020 may beselected from the group consisting of: chromium, copper, bismuth,cobalt, vanadium, titanium, rhodium, and beryllium.

In some implementations of the invention, various combinations of othersuperconducting materials (i.e., rather than HTS material 360) andmodifying materials may be used. For example, in some implementations ofthe invention, the superconducting material may be magnesium diboride(“MgB₂”). By itself, magnesium diboride has a transition temperature ofapproximately 39K. In some implementations of the invention, thesuperconducting material may be magnesium diboride and modifyingmaterial 1020 may be an oxygen bonding conductive material. In someimplementations of the invention, the superconducting material may bemagnesium diboride and modifying material 1020 may be selected from thegroup including, but not limited to: chromium, copper, bismuth, cobalt,vanadium, titanium, rhodium, or beryllium. In some implementations ofthe invention, the superconducting material may be magnesium diborideand modifying material 1020 may be selected from the group consistingof: chromium, copper, bismuth, cobalt, vanadium, titanium, rhodium, andberyllium.

In some implementations of the invention, modifying material 1020 may belayered onto a sample of HTS material 360 using various techniques forlayering one composition onto another composition as would beappreciated. For example, such layering techniques include, but are notlimited to, pulsed laser deposition, evaporation includingcoevaporation, e-beam evaporation and activated reactive evaporation,sputtering including magnetron sputtering, ion beam sputtering and ionassisted sputtering, cathodic arc deposition, CVD, organometallic CVD,plasma enhanced CVD, molecular beam epitaxy, a sol-gel process, liquidphase epitaxy and/or other layering techniques. In some implementationsof the invention, HTS material 360 may be layered onto a sample ofmodifying material 1020 using various techniques for layering onecomposition onto another composition. In some implementations of theinvention, a single atomic layer of modifying material 1020 (i.e., alayer of modifying material 1020 having a thickness substantially equalto a single atom or molecule of modifying material 1020) may be layeredonto a sample of HTS material 360. In some implementations of theinvention, a single unit layer of the modifying material (i.e., a layerof the modifying material having a thickness substantially equal to asingle unit (e.g., atom, molecule, crystal, or other unit) of themodifying material) may be layered onto a sample of the HTS material. Insome implementations of the invention, the HTS material may be layeredonto a single unit layer of the modifying material. In someimplementations of the invention, two or more unit layers of themodifying material may be layered onto the HTS material. In someimplementations of the invention, the HTS material may be layered ontotwo or more unit layers of the modifying material.

Others have attempted to layer various compositions (e.g., gold, copper,silicon, etc.) onto known HTS materials in an effort to improve theirusefulness in various applications. However, the selection of suchcompositions was not based on an intent to change, enhance or otherwisemaintain aperture 210, specifically with regard to: various geometriccharacteristics of crystalline structure 100 and aperture 210 (forexample, but not limited to, the width of the gap between first portion220 and second portion 230, size of aperture 210, etc.); atomiccharacteristics of aperture atoms 250 in crystalline structure 100,their interaction with each other and their impact on aperture 210 astemperature changes; and atomic characteristics of atoms in crystallinestructure 100 and their interaction with modifying material 1020 (forexample, but not limited to, various bonding properties of modifyingmaterial 1020 with atoms in crystalline structure 100).

In some implementations of the invention, changes to lattices usedwithin crystalline structure 100 may be made. For example, latticeshaving monoclinic crystal symmetries, orthorhombic crystal symmetries,or cubic crystal symmetries may be used to improve various otherlattices within crystalline structure 100. In addition, a body-centeredcubic symmetry or a face-centered cubic symmetry may be used to improvea simple cubic symmetry within crystalline structure 100. In someimplementations, a wider variety of lattices within crystallinestructure 100 may maintain aperture 210 at higher temperatures. In someimplementations, more complex lattices within crystalline structure 100may maintain aperture 210 at higher temperatures.

In some implementations of the invention, crystalline structure 100 maybe designed so that phonons (i.e., lattice vibrations) withincrystalline structure 100 predominately propagate through crystallinestructure 100 in a single direction that is parallel to the propagationof electrical charge through aperture 210 (i.e., into the page of, forexample, FIG. 2). Such phonons tend not to affect aperture 210 therebypermitting aperture 210 to operate in a superconducting state at highertemperatures. Any phonons propagating orthogonal to the propagation ofelectrical charge through aperture 210 may be minimized so as to avoidaffecting aperture 210.

FIGS. 12 and 13A-13I are now used to describe modifying a sample 1310 ofan HTS material 360 to produce a modified HTS material 1060 according tovarious implementations of the invention. FIG. 12 is a flowchart formodifying sample 1310 of HTS material 360 with a modifying material 1020to produce a modified HTS material 1060 according to variousimplementations of the invention. FIGS. 13A-13J illustrate sample 1310of HTS material 360 undergoing modifications to produce modified HTSmaterial 1060 according to various implementations of the invention. Insome implementations of the invention, HTS material 360 is amixed-valence copper-oxide perovskite material and modifying material1380 is an oxygen bonding conductive material. In some implementationsof the invention, HTS material 360 is an HTS material commonly referredto as YBCO and modifying material 1380 is chromium.

As illustrated in FIG. 13A, sample 1310 is a plurality of crystallineunit cells of HTS material 360 and is oriented with itsnon-superconducting axis along the c-axis. In some implementations ofthe invention, sample 1310 has dimensions of approximately 5 mm×10 mm×10mm. For purposes of this description, sample 1310 is oriented so that aprimary axis of conduction of HTS material 360 aligned along the a-axis.As would be apparent, if HTS material 360 includes two primary axes ofconduction, sample 1310 may be oriented along either the a-axis or theb-axis. As would be further appreciated, in some implementations sample1310 may be oriented along any line within the c-plane (i.e., a faceparallel with any ab-plane). In an operation 1210 and as illustrated inFIG. 13B and FIG. 13C, a slice 1320 is produced by cutting sample 1310along a plane substantially parallel to the a-plane of sample 1310. Insome implementations of the invention, slice 1320 is approximately 3 mmthick although other thicknesses may be used. In some implementations ofthe invention, this may be accomplished using a precision diamond blade.

In an optional operation 1220 and as illustrated in FIG. 13D, FIG. 13E,and FIG. 13F, a wedge 1330 is produced by cutting slice 1320 along adiagonal of the a-plane of slice 1320 to expose various apertures insample 1310. In some implementations of the invention, this isaccomplished using a precision diamond blade. This operation produces aface 1340 on the diagonal surface of wedge 1330 having exposedapertures. In some implementations of the invention, face 1340corresponds to any plane that is substantially parallel to the c-axis.In some implementations of the invention, face 1340 corresponds to aplane substantially perpendicular to the a-axis (i.e., the a-plane ofcrystalline structure 100). In some implementations of the invention,face 1340 corresponds to a plane substantially perpendicular to theb-axis (i.e., the b-plane of crystalline structure 100). In someimplementations of the invention, face 1340 corresponds to a planesubstantially perpendicular to any line in the ab-plane. In someimplementations of the invention, face 1340 corresponds to any planethat is not substantially perpendicular to the c-axis. In someimplementations of the invention, face 1340 corresponds to any planethat is not substantially perpendicular to any substantiallynon-superconducting axis of the HTS material 360. As would beappreciated, operation 1220 may not be necessary as slice 1320 may haveexposed apertures and/or other characteristics similar to thosediscussed above with reference to face 1340.

In an operation 1230 and as illustrated in FIG. 13G and FIG. 13J, amodifying material 1380 (e.g., modifying material 1020 as illustrated inFIG. 10 and elsewhere) is deposited onto face 1340 to produce a face1350 of modifying material 1380 on wedge 1330 and a modified region 1360of modified HTS material 1060 at an interface between face 1340 andmodifying material 1380. Modified region 1360 in wedge 1330 correspondsto a region in wedge 1330 where modifying material 1380 bonds tocrystalline structure 300 in accordance with various implementations ofthe invention to improve crystalline structure 300 in proximity toaperture 310. Other forms of bonding modifying material 1380 to HTSmaterial 360 may be used. Operation 1230 is described in further detailbelow in reference to FIG. 14.

Referring to FIG. 14, in an operation 1410, face 1340 is polished. Insome implementations of the invention, one or more polishes may be used.In some implementations of the invention that include YBCO as the HTSmaterial, one or more non-water-based polishes may be used, including,but not limited to isopropyl alcohol, heptane, non-organic or stableorganic slurries. In some implementations of the invention, water-basedpolishes may be used. In some implementations of the invention, face1340 is finally polished with a 20 nm colloidal slurry. In someimplementations of the invention, polishing of face 1340 is performed ina direction substantially parallel to the a-axis of wedge 1330 (i.e.,along a direction of apertures 310). In some implementations of theinvention, oxygen plasma ashing may be used as would be appreciated. Insome implementations of the invention, cleanliness of face 1340 (i.e.,absence of impurities or other materials, compositions, or compounds)just prior to layering modifying material 1380 thereon may be importantto achieving improved operational characteristics in the modified HTSmaterial over those of the unmodified HTS material.

In an operation 1420, one or more surfaces other than face 1340 aremasked. In some implementations, all surfaces other than face 1340 aremasked. In an operation 1430, modifying material 1380 is deposited ontoface 1340 using vapor deposition. In some implementations of theinvention, approximately 40 nm of modifying material 1380 is depositedonto face 1340 using vapor deposition, although smaller or largeramounts of modifying material 1380 may be used. In some implementationsof the invention, modifying material 1380 is deposited onto face 1340using vapor deposition under a vacuum, which may have a pressure of5×10⁻⁶ torr or less.

Referring to FIG. 12, FIG. 13H and FIG. 13I, in an optional operation1240, in some implementations of the invention, a portion of wedge 1330is removed to reduce a size of wedge 1330 to produce a wedge 1390. In anoperation 1250, double-ended leads are applied to each of the twoa-planes (i.e., “b-c” faces) of wedge 1390 using a bonding agent. Insome implementations of the invention, silver paste (Alfa Aesar silverpaste #42469) is used to apply double-ended leads to the two a-planes(i.e., “b-c” faces) of wedge 1390. In an operation 1260, the bondingagent is cured. In some implementations using silver paste as thebonding agent, the silver paste is cured for one hour at 60° C. and thencured for an additional hour at 150° C. Other curing protocols may beused as would be apparent. In some implementations of the invention, aconductive material, such as, but not limited to, silver, is sputteredor otherwise bonded onto each of the two b-c faces of wedge 1390 and thedouble-ended leads are attached thereto as would be apparent. Othermechanisms for attaching double-ended leads to wedge 490 may be used.After operation 1250, wedge 1390 with modified region 1360 (illustratedin FIG. 13J) is ready for testing.

FIG. 15 illustrates a test bed 1500 useful for determining variousoperational characteristics of wedge 1390. Test bed 1500 includes ahousing 1510 and four clamps 1520. Wedge 1390 is placed in housing 1510and each of the double-ended leads are clamped to housing 1510 usingclamps 1520 as illustrated. The leads are clamped to housing 1510 toprovide stress relief in order to prevent flexure and/or fracture of thecured silver paste. A current source is applied to one end of the pairof double-ended leads and a voltmeter measures voltage across the otherend of the pair of double-ended leads. This configuration provides amulti-point technique for determining resistance of wedge 1390, and inparticular, of modified HTS material 1060 as would be appreciated.

FIGS. 16A-16G illustrate test results 1600 obtained as described above.Test results 1600 include a plot of resistance of modified HTS material1060 as a function of temperature (in K). More particularly, testresults 1600 correspond to modified HTS material 1060 where modifyingmaterial 1380 corresponds to chromium and where HTS material 360corresponds to YBCO. FIG. 16A includes test results 1600 over a fullrange of temperature over which resistance of modified HTS material 1060was measured, namely 84K to 286K. In order to provide further detail,test results 1600 were broken into various temperature ranges andillustrated. In particular, FIG. 16B illustrates those test results 1600within a temperature range from 240K to 280K; FIG. 16C illustrates thosetest results 1600 within a temperature range from 210K to 250K; FIG. 16Dillustrates those test results 1600 within a temperature range from 180Kto 220K; FIG. 16E illustrates those test results 1600 within atemperature range from 150K to 190K; FIG. 16F illustrates those testresults 1600 within a temperature range from 120K to 160K; and FIG. 16Gillustrates those test results 1600 within a temperature range from84.5K to 124.5K.

Test results 1600 demonstrate that various portions of modified HTSmaterial 1060 within wedge 1390 operate in a superconducting state athigher temperatures relative to HTS material 360. Six sample analysistest runs were made using wedge 1390. For each sample analysis test run,test bed 1510, with wedge 1390 mounted therein, was slowly cooled fromapproximately 286K to 83K. While being cooled, the current sourceapplied +60 nA and −60 nA of current in a delta mode configurationthrough wedge 1390 in order to reduce impact of any DC offsets and/orthermocouple effects. At regular time intervals, the voltage acrosswedge 1390 was measured by the voltmeter. For each sample analysis testrun, the time series of voltage measurements were filtered using a512-point fast Fourier transform (“FFT”). All but the lowest 44frequencies from the FFT were eliminated from the data and the filtereddata was returned to the time domain. The filtered data from each sampleanalysis test run were then merged together to produce test results1600. More particularly, all the resistance measurements from the sixsample analysis test runs were organized into a series of temperatureranges (e.g., 80K-80.25K, 80.25K to 80.50, 80.5K to 80.75K, etc.) in amanner referred to as “binning.” Then the resistance measurements ineach temperature range were averaged together to provide an averageresistance measurement for each temperature range. These averageresistance measurements form test results 1600.

Test results 1600 include various discrete steps 1610 in the resistanceversus temperature plot, each of such discrete steps 1610 representing arelatively rapid change in resistance over a relatively narrow range oftemperatures. At each of these discrete steps 1610, discrete portions ofmodified HTS material 1060 begin propagating electrical charge up tosuch portions' charge propagating capacity at the respectivetemperatures. This behavior is described in reference to FIG. 13J, whichillustrates an interface between modifying material 1380 and HTSmaterial 360. At very small scales, face 1340 is not perfectly smooth.In fact, as illustrated, only portions of apertures 310 are exposedwithin face 1340 and hence only small portions of HTS material 360 maybe modified. Hence, apertures 310 within modified HTS material 1060typically do not extend across the entire width or length of wedge 1390.Accordingly, in some implementations of the invention, modifyingmaterial 1380 covers an entire surface of HTS material 360 and may actas a conductor that carries electrical charge between apertures 310.

Before discussing test results 1600 in further detail, variouscharacteristics of HTS material 360 and modifying material 1380 arediscussed. Resistance versus temperature (“R-T”) profiles of thesematerials individually are generally well known. The individual R-Tprofiles of these materials are not believed to include features similarto discrete steps 1610 found in test results 1600. In fact, unmodifiedsamples of HTS material 360 and samples of modifying material 1380 alonehave been tested under similar and often identical testing andmeasurement configurations. In each instance, the R-T profile of theunmodified samples of HTS material 360 and the R-T profile of themodifying material alone did not include any features similar todiscrete steps 1610. Accordingly, discrete steps 1610 are the result ofmodifying HTS material 360 with modifying material 1380 to maintainaperture 310 at increased temperatures thereby allowing modifiedmaterial 1380 to remain in a superconducting state at such increasedtemperatures in accordance with various implementations of theinvention.

At each of discrete steps 1610, various ones of apertures 310 withinmodified HTS material 1060 start propagating electrical charge up toeach aperture's 310 charge propagating capacity. As measured by thevoltmeter, each charge propagating aperture 310 appears as ashort-circuit, dropping the apparent voltage across wedge 1390 by asmall amount. The apparent voltage continues to drop as additional onesof apertures 310 start propagating electrical charge until thetemperature of wedge 1390 reaches the transition temperature of HTSmaterial 360 (i.e., the transition temperature of the unmodified HTSmaterial which in the case of YBCO is approximately 90K).

Test results 1600 indicate that certain apertures 310 within modifiedHTS material 1060 propagate electrical charge at approximately 97K. Inother words, test results indicate that certain apertures 310 withinmodified HTS material 1060 propagate electrical charge throughcrystalline structure of the modified HTS material 1060 at approximately97K. Test results 1600 also indicate that: certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately100K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 103K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately113K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 126K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately140K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 146K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately179K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 183.5K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately200.5K; certain apertures 310 within modified HTS material 1060propagate electrical charge at approximately 237.5K; and certainapertures 310 within modified HTS material 1060 propagate electricalcharge at approximately 250K. Certain apertures 310 within modified HTSmaterial 1060 may propagate electrical charge at other temperatureswithin the full temperature range as would be appreciated.

Test results 1600 include various other relatively rapid changes inresistance over a relatively narrow range of temperatures not otherwiseidentified as a discrete step 1610. Some of these other changes maycorrespond to artifacts from data processing techniques used on themeasurements obtained during the test runs (e.g., FFTs, filtering,etc.). Some of these other changes may correspond to changes inresistance due to resonant frequencies in modified crystalline structure1010 affecting aperture 310 at various temperatures. Some of these otherchanges may correspond to additional discrete steps 1610. In addition,changes in resistance in the temperature range of 270-274K are likely tobe associated with water present in modified HTS material 1060, some ofwhich may have been introduced during preparation of wedge 1380, forexample, but not limited to, during operation 1410.

In addition to discrete steps 1610, test results 1600 differ from theR-T profile of HTS material 360 in that modifying material 1380 conductswell at temperatures above the transition temperature of HTS material360 whereas HTS material 360 typically does not.

FIG. 24 illustrates additional test results 2400 for samples of HTSmaterial 360 and modifying material 1380. More particularly, for testresults 2400, modifying material 1380 corresponds to chromium and HTSmaterial 360 corresponds to YBCO. For test results 2400, samples of HTSmaterial 360 were prepared, using various techniques discussed above, toexpose a face of crystalline structure 300 parallel to the a-plane orthe b-plane. Test results 2400 were gathered using a lock-in amplifierand a K6221 current source, which applied a 10 nA current at 24.0, Hz tomodified HTS material 1060. Test results 2400 include a plot ofresistance of modified HTS material 1060 as a function of temperature(in K). FIG. 24 includes test results 2400 over a full range oftemperature over which resistance of modified HTS material 1060 wasmeasured, namely 80K to 275K. Test results 2400 demonstrate that variousportions of modified HTS material 1060 operate in a superconductingstate at higher temperatures relative to HTS material 360. Five sampleanalysis test runs were made with a sample of modified HTS material1060. For each sample analysis test run, the sample of modified HTSmaterial 1060 was slowly warmed from 80K to 275K. While being warmed,the voltage across the sample of modified HTS material 1060 was measuredat regular time intervals and the resistance was calculated based on thesource current. For each sample analysis test run, the time series ofresistance measurements were filtered using a 1024-point FFT. All butthe lowest 15 frequencies from the FFT were eliminated from the data andthe filtered resistance measurements were returned to the time domain.The filtered resistance measurements from each sample analysis test runwere then merged together using the binning process referred to above toproduce test results 2400. Then the resistance measurements in eachtemperature range were averaged together to provide an averageresistance measurement for each temperature range. These averageresistance measurements form test results 2400.

Test results 2400 include various discrete steps 2410 in the resistanceversus temperature plot, each of such discrete steps 2410 representing arelatively rapid change in resistance over a relatively narrow range oftemperatures, similar to discrete steps 1610 discussed above withrespect to FIGS. 16A-16G. At each of these discrete steps 2410, discreteportions of modified HTS material 1060 propagate electrical charge up tosuch portions' charge propagating capacity at the respectivetemperatures.

Test results 2400 indicate that certain apertures 310 within modifiedHTS material 1060 propagate electrical charge at approximately 120K. Inother words, test results 2400 indicate that certain apertures 310within modified HTS material 1060 propagate electrical charge throughcrystalline structure of the modified HTS material 1060 at approximately120K. Test results 2400 also indicate that: certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately145K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 175K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately200K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 225K; and certain apertures 310within modified HTS material 1060 propagate electrical charge atapproximately 250K. Certain apertures 310 within modified HTS material1060 may propagate electrical charge at other temperatures within thefull temperature range as would be appreciated.

FIGS. 25-29 illustrate additional test results for samples of HTSmaterial 360 and various modifying materials 1380. For these additionaltest results, samples of HTS material 360 were prepared, using varioustechniques discussed above, to expose a face of crystalline structure300 substantially parallel to the a-plane or the b-plane or somecombination of the a-plane or the b-plane and the modifying material waslayered onto these exposed faces. Each of these modified samples wasslowly cooled from approximately 300K to 80K. While being warmed, acurrent source applied a current in a delta mode configuration throughthe modified sample as described below. At regular time intervals, thevoltage across the modified sample was measured. For each sampleanalysis test run, the time series of voltage measurements were filteredin the frequency domain using an FFT by removing all but the lowestfrequencies, and the filtered measurements were returned to the timedomain. The number of frequencies kept is in general different for eachdata set. The filtered data from each of test runs were then binned andaveraged together to produce the test results illustrated in FIGS.25-29.

FIG. 25 illustrates test results 2500 including a plot of resistance ofmodified HTS material 1060 as a function of temperature (in K). For testresults 2500, modifying material 1380 corresponds to vanadium and HTSmaterial 360 corresponds to YBCO. Test results 2500 were produced over11 test runs using a 20 nA current source, a 1024-point FFT wasperformed, and information from all but the lowest 12 frequencies wereeliminated. Test results 2500 demonstrate that various portions ofmodified HTS material 1060 operate in a superconducting state at highertemperatures relative to HTS material 360. Test results 2500 includevarious discrete steps 2510 in the resistance versus temperature plot,similar to those discussed above with regard to FIGS. 16A-16G. Testresults 2500 indicate that: certain apertures 310 within modified HTSmaterial 1060 propagate electrical charge at approximately 267K; certainapertures 310 within modified HTS material 1060 propagate electricalcharge at approximately 257K; certain apertures 310 within modified HTSmaterial 1060 propagate electrical charge at approximately 243K; certainapertures 310 within modified HTS material 1060 propagate electricalcharge at approximately 232K; and certain apertures 310 within modifiedHTS material 1060 propagate electrical charge at approximately 219K.Certain apertures 310 within modified HTS material 1060 may propagateelectrical charge at other temperatures.

FIG. 26 illustrates test results 2600 include a plot of resistance ofmodified HTS material 1060 as a function of temperature (in K). For testresults 2600, modifying material 1380 corresponds to bismuth and HTSmaterial 360 corresponds to YBCO. Test results 2600 were produced over 5test runs using a 400 nA current source, a 1024-point FFT was performed,and information from all but the lowest 12 frequencies were eliminated.Test results 2600 demonstrate that various portions of modified HTSmaterial 1060 operate in a superconducting state at higher temperaturesrelative to HTS material 360. Test results 2600 include various discretesteps 2610 in the resistance versus temperature plot, similar to thosediscussed above with regard to FIGS. 16A-16G. Test results 2600 indicatethat: certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 262K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately235K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 200K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately172K; and certain apertures 310 within modified HTS material 1060propagate electrical charge at approximately 141K. Certain apertures 310within modified HTS material 1060 may propagate electrical charge atother temperatures.

FIG. 27 illustrates test results 2700 include a plot of resistance ofmodified HTS material 1060 as a function of temperature (in K). For testresults 2700, modifying material 1380 corresponds to copper and HTSmaterial 360 corresponds to YBCO. Test results 2500 were produced over 6test runs using a 200 nA current source, a 1024-point FFT was performed,and information from all but the lowest 12 frequencies were eliminated.Test results 2700 demonstrate that various portions of modified HTSmaterial 1060 operate in a superconducting state at higher temperaturesrelative to HTS material 360. Test results 2700 include various discretesteps 2710 in the resistance versus temperature plot, similar to thosediscussed above with regard to FIGS. 16A-16G. Test results 2700 indicatethat: certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 268K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately256K; certain apertures 310 within modified HTS material 1060 propagateelectrical charge at approximately 247K; certain apertures 310 withinmodified HTS material 1060 propagate electrical charge at approximately235K; and certain apertures 310 within modified HTS material 1060propagate electrical charge at approximately 223K. Certain apertures 310within modified HTS material 1060 may propagate electrical charge atother temperatures.

FIG. 28 illustrates test results 2800 include a plot of resistance ofmodified HTS material 1060 as a function of temperature (in K). For testresults 2800, modifying material 1380 corresponds to cobalt and HTSmaterial 360 corresponds to YBCO. Test results 2500 were produced over11 test runs using a 400 nA current source, a 1024-point FFT wasperformed, and information from all but the lowest 12 frequencies wereeliminated. Test results 2800 demonstrate that various portions ofmodified HTS material 1060 operate in a superconducting state at highertemperatures relative to HTS material 360. Test results 2800 includevarious discrete steps 2810 in the resistance versus temperature plot,similar to those discussed above with regard to FIGS. 16A-16G. Testresults 2800 indicate that: certain apertures 310 within modified HTSmaterial 1060 propagate electrical charge at approximately 265K; certainapertures 310 within modified HTS material 1060 propagate electricalcharge at approximately 236K; certain apertures 310 within modified HTSmaterial 1060 propagate electrical charge at approximately 205K; certainapertures 310 within modified HTS material 1060 propagate electricalcharge at approximately 174K; and certain apertures 310 within modifiedHTS material 1060 propagate electrical charge at approximately 143K.Certain apertures 310 within modified HTS material 1060 may propagateelectrical charge at other temperatures.

FIG. 29 illustrates test results 2900 include a plot of resistance ofmodified HTS material 1060 as a function of temperature (in K). For testresults 2900, modifying material 1380 corresponds to titanium and HTSmaterial 360 corresponds to YBCO. Test results 2500 were produced over25 test runs using a 100 nA current source, a 512-point FFT wasperformed, and information from all but the lowest 11 frequencies wereeliminated. Test results 2900 demonstrate that various portions ofmodified HTS material 1060 operate in a superconducting state at highertemperatures relative to HTS material 360. Test results 2900 includevarious discrete steps 2910 in the resistance versus temperature plot,similar to those discussed above with regard to FIGS. 16A-16G. Testresults 2900 indicate that: certain apertures 310 within modified HTSmaterial 1060 propagate electrical charge at approximately 266K; certainapertures 310 within modified HTS material 1060 propagate electricalcharge at approximately 242K; and certain apertures 310 within modifiedHTS material 1060 propagate electrical charge at approximately 217K.Certain apertures 310 within modified HTS material 1060 may propagateelectrical charge at other temperatures.

In other experiments, modifying material 1020 was layered onto a surfaceof HTS material 360 substantially parallel to the c-plane of crystallinestructure 300. These tests results (not otherwise illustrated)demonstrate that layering a surface of HTS material 360 parallel to thec-plane with modifying material 1020 did not produce any discrete stepssuch as those described above (e.g., discrete steps 1610). These testresults indicate that modifying a surface of HTS material 360 that isperpendicular to a direction in which HTS material 360 does not (ortends to not) exhibit the resistance phenomenon does not improve theoperating characteristics of the unmodified HTS material. In otherwords, modifying such surfaces of HTS material 360 may not maintainaperture 310. In accordance with various principles of the invention,modifying material should be layered with surfaces of the HTS materialthat are parallel to the direction in which HTS material does not (ortends to not) exhibit the resistance phenomenon. More particularly, andfor example, with regard to HTS material 360 (illustrated in FIG. 3),modifying material 1020 should be bonded to an “a-c” face or a “b-c”face of crystalline structure 300 (both of which faces are parallel tothe c-axis) in HTS material 360 (which tends not to exhibit theresistance phenomenon in the direction of the c-axis) in order tomaintain aperture 310.

FIG. 20 illustrates an arrangement 2000 including alternating layers ofHTS material 360 and a modifying material 1380 useful for propagatingadditional electrical charge according to various implementations of theinvention. Such layers may be deposited onto one another using variousdeposition techniques. Various techniques may be used to improvealignment of crystalline structures 300 within layers of HTS material360. Improved alignment of crystalline structures 300 may result inapertures 310 of increased length through crystalline structure 300which in turn may provide for operation at higher temperatures and/orwith increased charge propagating capacity. Arrangement 2000 providesincreased numbers of apertures 310 within modified HTS material 1060 ateach interface between adjacent layers of modifying material 1380 andHTS material 360. Increased numbers of apertures 310 may increase acharge propagating capacity of arrangement 2000.

In some implementations of the invention, any number of layers may beused. In some implementations of the invention, other HTS materialsand/or other modifying materials may be used. In some implementations ofthe invention, additional layers of other material (e.g., insulators,conductors, or other materials) may be used between paired layers of HTSmaterial 360 and modifying material 1380 to mitigate various effects(e.g., magnetic effects, migration of materials, or other effects) or toenhance the characteristics of the modified HTS material 1060 formedwithin such paired layers. In some implementations of the invention, notall layers are paired. In other words, arrangement 2000 may have one ormore extra (i.e., unpaired) layers of HTS material 360 or one or moreextra layers of modifying material 1380.

FIG. 23 illustrates additional of layers 2310 (illustrated as a layer2310A, a layer 2310B, a layer 2310C, and a layer 2310D) of modifiedcrystalline structure 1010 in modified HTS material 1060 according tovarious implementations of the invention. As illustrated, modified HTSmaterial 1060 includes various apertures 310 (illustrated as an aperture310A, an aperture 310B, and an aperture 310C) at different distancesinto material 1060 from modifying material 1020 that form bonds withatoms of crystalline structure 300 (of FIG. 3). Aperture 310A is nearestmodifying material 1020, followed by aperture 310B, which in turn isfollowed by aperture 310C, etc. In accordance with variousimplementations of the invention, an impact of modifying material 1020is greatest with respect to aperture 310A, followed by a lesser impactwith respect to aperture 310B, which in turn is followed by a lesserimpact with respect to aperture 310C, etc. According to someimplementations of the invention, modifying material 1020 should bettermaintain aperture 310A than either aperture 310B or aperture 310C due toaperture 310A's proximity to modifying material 1020; likewise,modifying material 1020 should better maintain aperture 310B thanaperture 310C due to aperture 310B's proximity to modifying material1020, etc. According to some implementations of the invention, modifyingmaterial 1020 should better maintain the cross-section of aperture 310Athan the cross-sections of either aperture 310B or aperture 310C due toaperture 310A's proximity to modifying material 1020; likewise,modifying material 1020 should better maintain the cross-section ofaperture 310B than the cross-section of aperture 310C due to aperture310B's proximity to modifying material 1020, etc. According to someimplementations of the invention, modifying material 1020 should have agreater impact on a charge propagating capacity of aperture 310A at aparticular temperature than on a charge propagating capacity of eitheraperture 310B or aperture 310C at that particular temperature due toaperture 310A's proximity to modifying material 1020; likewise,modifying material 1020 should have a greater impact on the chargepropagating capacity of aperture 310B at a particular temperature thanon the charge propagating capacity of aperture 310C at that particulartemperature due to aperture 310B's proximity to modifying material 1020,etc. According to some implementations of the invention, modifyingmaterial 1020 should enhance the propagation of electrical chargethrough aperture 310A more than the propagation of electrical chargethrough either aperture 310B or aperture 310C due to aperture 310A'sproximity to modifying material 1020; likewise, modifying material 1020should enhance the propagation of electrical charge through aperture310B more than the propagation of electrical charge through aperture310C due to aperture 310B's proximity to modifying material 1020, etc.

Various test results described above, for example, test results 1600 ofFIG. 16, among others, support these aspects of various implementationsof the invention, i.e., generally, that the impact of modifying material1020 on apertures 310 varies in relation to their proximity to oneanother. In particular, each discrete step 1610 in test results 1600 maycorrespond to a change in electrical charge carried by modified HTSmaterial 1060 as those apertures 310 in a particular layer 2310 (or moreappropriately, those apertures 310 formed between adjacent layers 2310as illustrated) propagate electrical charge up to such apertures' 310charge propagating capacity. Those apertures 310 in layers 2310 closerin proximity to modifying material 1020 correspond to discrete steps1610 at higher temperatures whereas those apertures 310 in layers 2310further from modifying material 1020 correspond to discrete steps 1610at lower temperatures. Discrete steps 1610 are “discrete” in the sensethat apertures 310 at a given relative distance to modifying material1020 (i.e., apertures 310A between layers 2310A and 2310B) propagateelectrical charge at a particular temperature and quickly reach theirmaximum charge propagating capacity. Another discrete step 1610 isreached when apertures 310 at an increased distance from modifyingmaterial 1020 (i.e., apertures 310B between layers 2310B and 2310C)propagate electrical charge at a lower temperature as a result of theincreased distance and hence the lessened impact of modifying material1020 on those apertures 310. Each discrete step 1610 corresponds toanother set of apertures 310 beginning to carry electrical charge basedon their distance from modifying material 1020. At some distance,however, modifying material 1020 may have insufficient impact on someapertures 310 to cause them to carry electrical charge at a highertemperature than they otherwise would; hence, such apertures 310propagate electrical charge at a temperature consistent with that of HTSmaterial 360.

In some implementations of the invention, a distance between modifyingmaterial 1020 and apertures 310 is reduced so as to increase impact ofmodifying material 1020 on more apertures 310. In effect, more apertures310 should propagate electrical charge at discrete steps 1610 associatedwith higher temperatures. For example, in arrangement 2000 of FIG. 20and in accordance with various implementations of the invention, layersof HTS material 360 may be made to be only a few unit cells thick inorder to reduce the distance between apertures 310 in HTS material 360and modifying material 1380. Reducing this distance should increase thenumber of apertures 310 impacted by modifying material 1380 at a giventemperature. Reducing this distance also increases the number ofalternating layers of HTS material 360 in a given overall thickness ofarrangement 2000 thereby increasing an overall charge propagatingcapacity of arrangement 2000.

FIG. 32 illustrates a film 3200 of an HTS material 3210 formed on asubstrate 3220, although, substrate 3220 may not be necessary in variousimplementations of the invention. In various implementations of theinvention, film 3200 may be formed into a tape having a length, forexample, greater than 10 cm, 1 m, 1 km or more. Such tapes may beuseful, for example, as HTS conductors or HTS wires. As would beappreciated, while various implementations of the invention aredescribed in reference to HTS films, such implementations apply to HTStapes as well.

For purposes of this description and as illustrated in FIG. 32, film3200 has a primary surface 3230 and a principal axis 3240. Principalaxis 3240 corresponds to a axis extending along a length of film 3200(as opposed to a width of film 3200 or a thickness of film 3200).Principal axis 3240 corresponds to a primary direction in whichelectrical charge flows through film 3200. Primary surface 3230corresponds to the predominant surface of film 3200 as illustrated inFIG. 32, and corresponds to the surface bound by the width and thelength of film 3200. It should be appreciated that films 3200 may havevarious lengths, widths, and/or thicknesses without departing from thescope of the invention.

In some implementations of the invention, during the fabrication of film3200, the crystalline structures of HTS material 3210 may be orientedsuch that their c-axis is substantially perpendicular to primary surface3230 of film 3200 and either the a-axis or the b-axis of theirrespective crystalline structures is substantially parallel to principalaxis 3240. Hence, as illustrated in FIG. 32, the c-axis is referenced byname and the a-axis and the b-axis are not specifically labeled,reflecting their interchangeability for purposes of describing variousimplementations of the invention. In some fabrication processes of film3200, the crystalline structures of HTS material may be oriented suchthat any given line within the c-plane may be substantially parallelwith principal axis 3240.

For purposes of this description, films 3200 having the c-axis of theirrespective crystalline structures oriented substantially perpendicularto primary surface 3230 (including film 3200 depicted in FIG. 32) arereferred to as “c-films” (i.e., c-film 3200). C-film 3200, with HTSmaterial 3210 comprised of YBCO, is commercially available from, forexample, American Superconductors™ (e.g., 344 Superconductor™ Type 348C)or Theva Dünnschichttechnik GmbH (e.g., HTS coated conductors).

In some implementations of the invention, substrate 3220 may include asubstrate material including, but not limited to, MgO, STO, LSGO, apolycrystalline material such as a metal or a ceramic, an inert oxidematerial, a cubic oxide material, a rare earth oxide material, or othersubstrate material as would be appreciated.

According to various implementations of the invention (and as describedin further detail below), a modifying material (e.g., modifying material1020, 1380) is layered onto an appropriate surface of HTS material 3210,where the appropriate surface of HTS material 3210 corresponds to anysurface not substantially perpendicular to the c-axis of the crystallinestructure of HTS material 3210. In other words, the appropriate surfaceof HTS material 3210 may correspond to any surface that is notsubstantially parallel to the primary surface 3230. In someimplementations of the invention, the appropriate surface of HTSmaterial 3210 may correspond to any surface that is substantiallyparallel to the c-axis of the crystalline structure of HTS material3210. In some implementations of the invention, the appropriate surfaceof HTS material 3210 may correspond to any surface that is notsubstantially perpendicular to the c-axis of the crystalline structureof HTS material 3210. In order to modify an appropriate surface ofc-film 3200 (whose primary surface 3230 is substantially perpendicularto the c-axis of the crystalline structure of HTS material 3210), theappropriate surface of HTS material 3210 may be formed on or withinc-film 3200. In some implementations of the invention, primary surface3230 may be processed to expose appropriate surface(s) of HTS material3210 on or within c-film 3200 on which to layer modifying material. Insome implementations of the invention, primary surface 3230 may beprocessed to expose one or more apertures 210 of HTS material 3210 on orwithin c-film 3200 on which to layer modifying material. It should beappreciated, that in various implementations of the invention, modifyingmaterial may be layered onto primary surface 3230 in addition to theappropriate surfaces referenced above.

Processing of primary surface 3230 of c-film 3200 to expose appropriatesurfaces and/or apertures 210 of HTS material 3210 may comprise variouspatterning techniques, including various wet processes or dry processes.Various wet processes may include lift-off, chemical etching, or otherprocesses, any of which may involve the use of chemicals and which mayexpose various other surfaces within c-film 3200. Various dry processesmay include ion or electron bream irradiation, laser direct-writing,laser ablation or laser reactive patterning or other processes which mayexpose various appropriate surfaces and/or apertures 210 of HTS material3210 within c-film 3200.

As illustrated in FIG. 33, primary surface 3230 of c-film 3200 may beprocessed to expose an appropriate surface within c-film 3200. Forexample, c-film 3200 may be processed to expose a face within c-film3200 substantially parallel to the b-plane of crystalline structure 100or a face within c-film 3200 substantially parallel to the a-plane ofcrystalline structure 100. More generally, in some implementations ofthe invention, primary surface 3230 of c-film 3200 may be processed toexpose an appropriate surface within c-film 3200 corresponding to ana/b-c face (i.e., a face substantially parallel to ab-plane). In someimplementations of the invention, primary surface 3230 of c-film may beprocessed to expose any face within c-film 3200 that is notsubstantially parallel with primary surface 3230. In someimplementations of the invention, primary surface 3230 of c-film may beprocessed to expose any face within c-film 3200 that is notsubstantially parallel with primary surface 3230 and also substantiallyparallel with principal axis 3240. Any of these faces, includingcombinations of these faces, may correspond to appropriate surfaces ofHTS material 3210 on or within c-film 3200. According to variousimplementations of the invention, appropriate surfaces of HTS material3210 provide access to or otherwise “expose” apertures 210 in HTSmaterial 3210 for purposes of maintaining such apertures 210.

In some implementations of the invention, as illustrated in FIG. 33,primary surface 3230 is processed to form one or more grooves 3310 inprimary surface 3230. Grooves 3310 include one or more appropriatesurfaces (i.e., surfaces other than one substantially parallel toprimary surface 3230) on which to deposit modifying material. Whilegrooves 3310 are illustrated in FIG. 33 as having a cross sectionsubstantially rectangular in shape, other shapes of cross sections maybe used as would be appreciated. In some implementations of theinvention, the width of grooves 3310 may be greater than 10 nm. In someimplementations of the invention and as illustrated in FIG. 33, thedepth of grooves 3310 may be less than a full thickness of HTS material3210 of c-film 3200. In some implementations of the invention and asillustrated in FIG. 34, the depth of grooves 3310 may be substantiallyequal to the thickness of HTS material 3210 of c-film 3200. In someimplementations of the invention, the depth of grooves 3310 may extendthrough HTS material 3210 of c-film 3200 and into substrate 3220 (nototherwise illustrated). In some implementations of the invention, thedepth of grooves 3310 may correspond to a thickness of one or more unitsof HTS material 3210 (not otherwise illustrated). Grooves 3310 may beformed in primary surface 3230 using various techniques, such as, butnot limited to, laser etching, or other techniques.

In some implementations of the invention, the length of grooves 3310 maycorrespond to the full length of c-film 3200. In some implementations ofthe inventions, grooves 3310 are substantially parallel to one anotherand to principal axis 3240. In some implementations of the invention,grooves 3310 may take on various configurations and/or arrangements inaccordance with the various aspects of the invention. For example,grooves 3310 may extend in any manner and/or direction and may includelines, curves and/or other geometric shapes in cross-section withvarying sizes and/or shapes along its extent.

While various aspects of the invention are described as forming grooves3310 within primary surface 3230, it will be appreciated that bumps,angles, or protrusions that include appropriate surfaces of HTS material3210 may be formed on substrate 3220 to accomplish similar geometries.

According to various implementations of the invention, c-film 3200 maybe modified to form various modified c-films. For example, referring toFIG. 35, a modifying material 3520 (i.e., modifying material 1020,modifying material 1380) may be layered onto primary surface 3230 andinto grooves 3310 formed within primary surface 3230 of an unmodifiedc-film (e.g., c-film 3200) and therefore onto various appropriatesurfaces 3510 to form a modified c-film 3500. Appropriate surfaces 3510may include any appropriate surfaces discussed above. While appropriatesurfaces 3510 are illustrated in FIG. 35 as being perpendicular toprimary surface 3230, this is not necessary as would be appreciated fromthis description.

In some implementations of the invention, modifying material 3520 may belayered onto primary surface 3230 and into grooves 3310 as illustratedin FIG. 35. In some implementations, such as illustrated in FIG. 36,modifying material 3520 may be removed from primary surface 3230 to formmodified c-film 3600 using various techniques such that modifyingmaterial 3520 remains only in grooves 3310 (e.g., various polishingtechniques). In some implementations, modified c-film 3600 may beaccomplished by layering modifying material 3520 only in grooves 3310.In other words, in some implementations, modifying material 3520 may belayered only into grooves 3310 and/or onto appropriate surfaces 3510,without layering modifying material 3520 onto primary surface 3230 ormay be layered such that modifying material 3520 does not bond orotherwise adhere to primary surface 3230 (e.g., using various maskingtechniques). In some implementations of the invention, various selectivedeposition techniques may be employed to layer modifying material 3520directly onto appropriate surfaces 3510.

The thickness of modifying material 3520 in grooves 3310 and/or onprimary surface 3230 may vary according to various implementations ofthe invention. In some implementations of the invention, a single unitlayer of modifying material 3520 (i.e., a layer having a thicknesssubstantially equal to a single unit of modifying material 3520) may belayered onto appropriate surfaces 3510 of grooves 3310 and/or on primarysurface 3230. In some implementations of the invention, two or more unitlayers of modifying material 3520 may be layered into onto appropriatesurfaces 3510 of grooves 3310 and/or on primary surface 3230.

Modified c-films 3500, 3600 (i.e., c-film 3200 modified with modifyingmaterial 3520) in accordance with various implementations of theinvention may be useful for achieving one or more improved operationalcharacteristics over those of unmodified c-film 3200.

As illustrated in FIG. 37, in some implementations of the invention,primary surface 3230 of unmodified c-film 3200 may be modified, via achemical etch, to expose or otherwise increase an area of appropriatesurfaces 3510 available on primary surface 3230. In some implementationsof the invention, one manner of characterizing an increased area ofappropriate surfaces 3510 within primary surface 3230 may be based onthe root mean square (RMS) surface roughness of primary surface 3230 ofc-film 3200. In some implementations of the invention, as a result ofchemical etching, primary surface 3230 of c-film 3200 may include anetched surface 3710 having a surface roughness in a range of about 1 nmto about 50 nm. RMS surface roughness may be determined using, forexample, Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy(STM), or SEM and may be based on a statistical mean of an R-range,wherein the R-range may be a range of the radius (r) of a grain size aswould be appreciated. After the chemical etch, an etched surface 3710 ofc-film 3700 may correspond to appropriate surface 3510 of HTS material3210.

As illustrated in FIG. 38, after the chemical etch, modifying material3520 may be layered on to etched surface 3710 of c-film 3700 to form amodified c-film 3800. Modifying material 3520 may cover substantiallyall of surface 3710 and the thickness of modifying material 3520 mayvary in accordance with various implementations of the invention. Insome implementations of the invention, a single unit layer of modifyingmaterial 3520 may be layered onto etched surface 3710. In someimplementations of the invention, two or more unit layers of modifyingmaterial 3520 may be layered onto etched surface 3710.

In some implementations of the invention, films having orientations ofcrystalline structure of HTS material other than that of c-film 3200 maybe used. For example, in reference to FIG. 39, and according to variousimplementations of the invention, instead of the c-axis orientedperpendicular to primary surface 3230 as with c-film 3200, a film 3900may have the c-axis oriented perpendicular to the principal axis 3240and a b-axis of HTS material 3910 oriented perpendicular to primarysurface 3230. Similarly, a film 3900 may have the c-axis orientedperpendicular to the principal axis 3240 and an a-axis of HTS material3910 oriented perpendicular to primary surface 3230. In someimplementations of the invention, film 3900 may have the c-axis orientedperpendicular to the principal axis 3240 and any line parallel to thec-plane oriented along principal axis 3240. As illustrated in FIG. 39,in these implementations of the invention, film 3900 includes HTSmaterial 3910 with the c-axis of its crystalline structure orientedperpendicular to principal axis 3240 and parallel to a primary surface3930 and are generally referred to herein as a-b films 3900. While FIG.39 illustrates the other two axes of the crystalline structure in aparticular orientation, such orientation is not necessary as would beappreciated. As illustrated, a-b films 3900 may include an optionalsubstrate 3220 (as with c-films 3200).

In some implementations of the invention, a-b film 3900 is an a-film,having the c-axis of the crystalline structure of HTS material 3910oriented as illustrated in FIG. 39 and the a-axis perpendicular toprimary surface 3930. Such a-films may be formed via various techniquesincluding those described at Selvamanickam, V., et al., “High CurrentY—Ba—Cu—O Coated Conductor using Metal Organic Chemical Vapor Depositionand Ion Beam Assisted Deposition,” Proceedings of the 2000 AppliedSuperconductivity Conference, Virginia Beach, Va., Sep. 17-22, 2000,which is incorporated herein by reference in its entirety. In someimplementations, a-films may be grown on substrates 3220 formed of thefollowing materials: LGSO, LaSrAlO₄, NdCaAIO₄, Nd₂CuO₄, or CaNdAlO₄.Other substrate materials may be used as would be appreciated.

In some implementations of the invention, a-b film 3900 is a b-film,having the c-axis of the crystalline structure of HTS material 3910oriented as illustrated in FIG. 39 and the b-axis perpendicular toprimary surface 3930.

According to various implementations of the invention, primary surface3930 of a-b film 3900 corresponds to an appropriate surface 3510. Insome implementations that employ a-b film 3900, forming an appropriatesurface of HTS material 3910 may include forming a-b film 3900.Accordingly, for implementations of the invention that include a-b film3900, modifying material 3520 may be layered onto primary surface 3930of a-b film 3900 to create a modified a-b film 4000 as illustrated inFIG. 40. In some implementations of the invention, modifying material3520 may cover primary surface 3930 of a-b film 3900 in whole or inpart. In some implementations of the invention, the thickness ofmodifying material 3520 may vary as discussed above. More particularly,in some implementations of the invention, a single unit layer ofmodifying material 3520 may be layered onto primary surface 3930 of a-bfilm 3900; and in some implementations of the invention, two or moreunit layers of modifying material 3520 may be layered onto primarysurface 3930 of a-b film 3900. In some implementations of the invention,a-b film 3900 may be grooved or otherwise modified as discussed abovewith regard to c-film 3200, for example, to increase an overall area ofappropriate surfaces 3510 of HTS material 3910 on which to layermodifying material 3520.

As would be appreciated, rather than utilizing a-b film 3900, someimplementations of the invention may utilize a layer of HTS material3210 having its crystalline structure oriented in a manner similar tothat of a-b film 3900.

In some implementations of the invention (not otherwise illustrated) abuffer or insulating material may be subsequently layered onto modifyingmaterial 3520 of any of the aforementioned films. In theseimplementations, the buffer or insulating material and the substrateform a “sandwich” with HTS material 3210, 3910 and modifying material3520 there between. The buffer or insulating material may be layeredonto modifying material 3520 as would be appreciated.

Any of the aforementioned materials may be layered onto any othermaterial. For example, HTS materials may be layered onto modifyingmaterials. Likewise, modifying materials may be layered onto HTSmaterials. Further, layering may include combining, forming, ordepositing one material onto the other material as would be appreciated.Layering may use any generally known layering technique, including, butnot limited to, pulsed laser deposition, evaporation includingcoevaporation, e-beam evaporation and activated reactive evaporation,sputtering including magnetron sputtering, ion beam sputtering and ionassisted sputtering, cathodic arc deposition, CVD, organometallic CVD,plasma enhanced CVD, molecular beam epitaxy, a sol-gel process, liquidphase epitaxy and/or other layering technique.

Multiple layers of HTS material 3210, 3910, modifying material 3520,buffer or insulating layers, and/or substrates 1120 may be arranged invarious implementations of the invention. FIG. 41 illustrates variousexemplary arrangements of these layers in accordance with variousimplementations of the invention. In some implementations, a given layermay comprise a modifying material 3520 that also acts as a buffer orinsulating layer or a substrate. Other arrangements or combinations ofarrangements may be used as would be appreciated from reading thisdescription. Furthermore, in some implementations of the invention,various layers of HTS material may have different orientations from oneanother in a given arrangement. For example, one layer of HTS materialin an arrangement may have the a-axis of its crystalline structureoriented along the principal axis 3240 and another layer of the HTSmaterial in the arrangement may have the b-axis of its crystallinestructure oriented along the principal axis 3240. Other orientations maybe used within a given arrangement in accordance with variousimplementations of the invention.

FIG. 42 illustrates a process for creating a modified HTS materialaccording to various implementations of the invention. In an operation4210, an appropriate surface 3510 is formed on or within an HTSmaterial. In some implementations of the invention where HTS materialexists as HTS material 3210 of c-film 3200, appropriate surface 3510 isformed by exposing appropriate surface(s) 3510 on or within primarysurface 3230 of a c-film 3200. In some implementations of the invention,appropriate surfaces of HTS material 3210 may be exposed by modifyingprimary surface 3230 using any of the wet or dry processing techniques,or combinations thereof, discussed above. In some implementations of theinvention, primary surface 3230 may be modified by chemical etching asdiscussed above.

In some implementations of the invention where HTS material exists asHTS material 3910 of a-b film 3900 (with or without substrate 3220),appropriate surface 3510 is formed by layering HTS material 3910 (in aproper orientation as described above) onto a surface, which may or maynot include substrate 3220.

In some implementations of the invention, appropriate surfaces 3510include surfaces of HTS material parallel to the ab-plane. In someimplementations of the invention, appropriate surfaces 3510 includefaces of HTS material parallel to the b-plane. In some implementationsof the invention, appropriate surfaces 3510 include faces of HTSmaterial parallel to the a-plane. In some implementations of theinvention, appropriate surfaces 3510 include one or more faces of HTSmaterial parallel to different ab-planes. In some implementations of theinvention, appropriate surfaces 3510 include one or more faces notsubstantially perpendicular to the c-axis of HTS material.

In some implementations of the invention, various optional operationsmay be performed. For example, in some implementations of the invention,appropriate surfaces 3510 or HTS material may be annealed. In someimplementations of the invention, this annealing may be a furnace annealor a rapid thermal processing (RTP) anneal process. In someimplementations of the invention, such annealing may be performed in oneor more annealing operations within predetermined time periods,temperature ranges, and other parameters. Further, as would beappreciated, annealing may be performed in the chemical vapor deposition(CVD) chamber and may include subjecting appropriate surfaces 3510 toany combination of temperature and pressure for a predetermined timewhich may enhance appropriate surfaces 3510. Such annealing may beperformed in a gas atmosphere and with or without plasma enhancement.

In an operation 4220, modifying material 3520 may be layered onto one ormore appropriate surfaces 3510. In some implementations of theinvention, modifying material 3520 may be layered onto appropriatesurfaces 3510 using various layering techniques, including various onesdescribed above.

FIG. 43 illustrates an example of additional processing that may beperformed during operation 4220 according to various implementations ofthe invention. In an operation 4310, appropriate surfaces 3510 may bepolished. In some implementations of the invention, one or more polishesmay be used as discussed above.

In an operation 4320, various surfaces other than appropriate surfaces3510 may be masked using any generally known masking techniques. In someimplementations, all surfaces other than appropriate surfaces 3510 maybe masked. In some implementations of the invention, one or moresurfaces other than appropriate surfaces 3510 may be masked.

In an operation 4330, modifying material 3520 may be layered on to (orin some implementations and as illustrated in FIG. 43, deposited on to)appropriate surfaces 3510 using any generally known layering techniquesdiscussed above. In some implementations of the invention, modifyingmaterial 3520 may be deposited on to appropriate surfaces 3510 usingMBE. In some implementations of the invention, modifying material 3520may be deposited on to appropriate surfaces 3510 using PLD. In someimplementations of the invention, modifying material 3520 may bedeposited on to appropriate surfaces 3510 using CVD. In someimplementations of the invention, approximately 40 nm of modifyingmaterial 3520 may be deposited on to appropriate surfaces 3510, althoughas little as 1.7 nm of certain modifying materials 3520 (e.g., cobalt)has been tested. In various implementations of the invention, muchsmaller amounts of modifying materials 3250, for example, on the orderof a few angstroms, may be used. In some implementation of theinvention, modifying material 3520 may be deposited on to appropriatesurfaces 3510 in a chamber under a vacuum, which may have a pressure of5×10⁻⁶ torr or less. Various chambers may be used including those usedto process semiconductor wafers. In some implementations of theinvention, the CVD processes described herein may be carried out in aCVD reactor, such as a reaction chamber available under the tradedesignation of 7000 from Genus, Inc. (Sunnyvale, Calif.), a reactionchamber available under the trade designation of 5000 from AppliedMaterials, Inc. (Santa Clara, Calif.), or a reaction chamber availableunder the trade designation of Prism from Novelus, Inc. (San Jose,Calif.). However, any reaction chamber suitable for performing MBE, PLDor CVD may be used.

FIG. 44 illustrates a process for forming a modified HTS materialaccording to various implementations of the invention. In particular,FIG. 44 illustrates a process for forming and/or modifying an a-b film3900. In an optional operation 4410, a buffer layer is deposited onto asubstrate 3220. In some implementations of the invention, the bufferlayer includes PBCO or other suitable buffer material. In someimplementations of the invention, substrate 3220 includes LSGO or othersuitable substrate material. In an operation 4420, HTS material 3910 islayered onto substrate 3220 with a proper orientation as described abovewith respect to FIG. 39. As would be appreciated, depending on optionaloperation 4410, HTS material 3910 is layered onto substrate 3220 or thebuffer layer. In some implementations of the invention, the layer of HTSmaterial 3910 is two or more unit layers thick. In some implementationsof the invention, the layer of HTS material 3910 is a few unit layersthick. In some implementations of the invention, the layer of HTSmaterial 3910 is several unit layers thick. In some implementations ofthe invention, the layer of HTS material 3910 is many unit layers thick.In some implementations of the invention, HTS material 3910 is layeredonto substrate 3220 using an IBAD process. In some implementations ofthe invention, HTS material 3910 is layered onto substrate 3220 whilesubject to a magnetic field to improve an alignment of the crystallinestructures within HTS material 3910.

In an optional operation 4430, appropriate surface(s) 3510 (which withrespect to a-b films 3900, corresponds to primary surface 3930) of HTSmaterial 3910 is polished using various techniques described above. Insome implementations of the invention, the polishing is accomplishedwithout introducing impurities onto appropriate surfaces 3510 of HTSmaterial 3910. In some implementations of the invention, the polishingis accomplished without breaking the clean chamber. In an operation4440, modifying material 3520 is layered onto appropriate surfaces 3510.In an optional operation 4450, a covering material, such as, but notlimited to, silver, is layered over entire modifying material 3520.

The flowcharts, illustrations, and block diagrams of the figuresillustrate the architecture, functionality, and operation of possibleimplementations of methods and products according to variousimplementations of the invention. It should also be noted that, in somealternative implementations, the functions noted in the blocks may occurout of the order noted in the figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved.

Furthermore, although the foregoing description is directed towardvarious implementations of the invention, it is noted that othervariations and modifications will be apparent to those skilled in theart, and may be made without departing from the spirit or scope of theinvention. Moreover, various features described in connection with oneimplementation of the invention may be used in conjunction orcombination with various other features or other implementationsdescribed herein, even if not expressly stated above.

What is claimed is:
 1. An HTS film comprising: a first layer comprisedof an HTS material, wherein the HTS material has a crystallinestructure; and a second layer comprised of a modifying material bondedto a face of the HTS material of the first layer, wherein the face ofthe HTS material is not substantially parallel to a c-plane of thecrystalline structure of the HTS material, wherein the HTS materialbonded to the modifying material has an improved operationalcharacteristic over the operational characteristics of the HTS materialwithout the modifying material.
 2. The HTS film of claim 1, wherein theimproved operational characteristic comprises a higher transitiontemperature.
 3. The HTS film of claim 1, further comprising a thirdlayer comprised of a substrate material.
 4. The HTS film of claim 3,wherein the first layer is adjacent the substrate layer.
 5. The HTS filmof claim 3, wherein the second layer is adjacent the substrate layer. 6.The HTS film of claim 1, further comprising a buffer or an insulatinglayer.
 7. The HTS film of claim 6, wherein the first layer is adjacentthe buffer or the insulating layer.
 8. The HTS film of claim 6, whereinthe second layer is adjacent the buffer or the insulating layer.
 9. TheHTS film of claim 1, further comprising a third layer of HTS materialbonded to the second layer.
 10. The HTS film of claim 1, furthercomprising a third layer of modifying material bonded to the firstlayer.
 11. The HTS film of claim 3, wherein the substrate materialcomprises a polycrystalline material, a polycrystalline metal, an alloy,a Hastelloy metal, a Haynes metal, or an Inconel metal.
 12. The HTS filmof claim 1, wherein the modifying material comprises chromium, copper,bismuth, cobalt, vanadium, titanium, rhodium, beryllium, gallium,selenium, or other material.
 13. The HTS film of claim 1, wherein theHTS material comprises a mixed-valence copper-oxide perovskite.